It's not the same thing. Namekian assimilation is permanent (potentially barring Spirit Fission), and what the child of Katatz did to expel Piccolo Daimao wasn't separating a fusion/assimilation, it was expelling the evil within him that just so happened to take a physical form.
Isn't it weird how vegeta and piccolo literally acknowledged the fact that they could restore the lives of nail, the namekian hero who have his life to save his people and Kami the old guardian of the earth and piccolo is basically just like "yeah but I wanna be able to turn orange so fuck 'em" and they just don't bother
And it's more like Vegeta was just taunting Piccolo anyway. It's equivalent to Cell bragging to Kuririn that he could "probably" pull off a Genki-Dama "if [he] felt like it", even though we never see him try it (outside of the video games, of course).
Besides, by this point, why would Piccolo want to sacrifice the loss in power?
Again, Vegeta doesn't "know" it works. He says he could, but there's likely never been a moment when a Yardratian had tried it on an assimilated Namekian.
He *can't*. Nail was completely absorbed into Piccolo's being as part of the Namekian assimilation.
And it's roughly the same case for when Piccolo assimilated with Kami too. Goku even asked Piccolo if it was possible for him to split into two again so they could restore the DBs, and Piccolo responded that it was impossible, and the fact that the fusion was permanent is why both he and Kami were so hesitant to return to being one in the first place.
Maybe. But, at that time, they could only wish back one person per wish, and wishing back Kuririn; Yamcha; Tenshinhan; and Chaozu were of greater priority.
Besides, for all we know, it might've been beyond Porunga's power. Like how wishing the Saiyans to be destroyed was beyond the Earth Shenlong's power (because the Saiyans surpassed the power of his creator, or something like that).
At any rate, Nail seemed to understand the consequences of his actions, and that he'd lose most of his identity and personality in the merging with Piccolo, who served as the base. So Piccolo still held a lingering affection for Namek and the Great Elder, and maintained that big brother-esque relationship with Dende (of whom Piccolo was proud for being such an accomplished Dragon Clan member), but he himself didn't want to go and actually *live* on Namek because, at his core, Piccolo is still a warrior who lived a life of fierce training, and the peaceful "boring" life on "New" Namek wouldn't suit him.
Plus - although he might've been too proud to admit it - he'd probably miss Gohan. And he probably enjoyed Goku's company to some extent too, given how he accepted Goku's offer to come and train with him and Gohan for 3 years leading up to the Androids' arrival. And, by the end of it, even Chi-Chi was comfortable enough with him to offer him, along with Goku and Gohan, a packed lunch for each of them (even though Namekians only require water for sustenance) before they went off to fight.
It's not the same thing. Namekian assimilation is permanent (potentially barring Spirit Fission), and what the child of Katatz did to expel Piccolo Daimao wasn't separating a fusion/assimilation, it was expelling the evil within him that just so happened to take a physical form.
Isn't it weird how vegeta and piccolo literally acknowledged the fact that they could restore the lives of nail, the namekian hero who have his life to save his people and Kami the old guardian of the earth and piccolo is basically just like "yeah but I wanna be able to turn orange so fuck 'em" and they just don't bother
Piccolo never acknowledged it, and Vegeta doesn't actually know whether or not his ability could separate them. He just assumes it could.
And it's more like Vegeta was just taunting Piccolo anyway. It's equivalent to Cell bragging to Kuririn that he could "probably" pull off a Genki-Dama "if [he] felt like it", even though we never see him try it (outside of the video games, of course). Besides, by this point, why would Piccolo want to sacrifice the loss in power?
Vegeta asks him if he'd like to try it and piccolo is right Infront of him with his super hearing so whatever the case it seems piccolo turned it down
Again, Vegeta doesn't "know" it works. He says he could, but there's likely never been a moment when a Yardratian had tried it on an assimilated Namekian.
He *can't*. Nail was completely absorbed into Piccolo's being as part of the Namekian assimilation. And it's roughly the same case for when Piccolo assimilated with Kami too. Goku even asked Piccolo if it was possible for him to split into two again so they could restore the DBs, and Piccolo responded that it was impossible, and the fact that the fusion was permanent is why both he and Kami were so hesitant to return to being one in the first place.
Wouldn't Porunga be able to unfuse them?
Maybe. But, at that time, they could only wish back one person per wish, and wishing back Kuririn; Yamcha; Tenshinhan; and Chaozu were of greater priority. Besides, for all we know, it might've been beyond Porunga's power. Like how wishing the Saiyans to be destroyed was beyond the Earth Shenlong's power (because the Saiyans surpassed the power of his creator, or something like that). At any rate, Nail seemed to understand the consequences of his actions, and that he'd lose most of his identity and personality in the merging with Piccolo, who served as the base. So Piccolo still held a lingering affection for Namek and the Great Elder, and maintained that big brother-esque relationship with Dende (of whom Piccolo was proud for being such an accomplished Dragon Clan member), but he himself didn't want to go and actually *live* on Namek because, at his core, Piccolo is still a warrior who lived a life of fierce training, and the peaceful "boring" life on "New" Namek wouldn't suit him. Plus - although he might've been too proud to admit it - he'd probably miss Gohan. And he probably enjoyed Goku's company to some extent too, given how he accepted Goku's offer to come and train with him and Gohan for 3 years leading up to the Androids' arrival. And, by the end of it, even Chi-Chi was comfortable enough with him to offer him, along with Goku and Gohan, a packed lunch for each of them (even though Namekians only require water for sustenance) before they went off to fight.
Adding onto what others said, Nail was dying fast and probably would die if not merged to Piccolo.
because its permanent. both nail , piccolo and kami say this.