PP is one of my favorite cause I always viewed every Pokemon(bar Lucario. Mewtwo is close, but only takes a few notes from the anime, though there's no denying its popularity there helped get it into Smash too) as being basically the generic but popular species being done. I wasn't even surprised. I'd have believed they were meant to be "unique characters" if the bios in Smash 64 didn't literally use their Pokedex entry. And Pikachu wasn't "male" so much as "has no other design". It got a female alt in Ultimate as well, further removing the defining idea it's supposed to be Ash's Pikachu(which it was clearly inspired from, but that's about it). A lot of Pokemon are inspired by the anime, but the only one heavily focused on it was Lucario at best. The rest just takes notes if anything. Squirtle, Ivysaur, and Incineroar have no notes from the anime at all. Greninja didn't till Ultimate, and that's after Ash-Greninja became hyper popular enough to make it into the core games(being the first time Ash is in the regular canon in some way, even by proxy).
I hope we get more characters like PP at some point. They're awesome and contains tons of cool moveset potential. Plus, many know by now I don't buy the poor argument it's not a character when the only thing a character is is any being in a fictional work. Some just lack characterization(which PP clearly does not, being a combination of more than one species. Not too different from OOT Link having the Boomerang, Upthrust, and Downthrust. I'd like to note Mario using the Fireball, which isn't possible in Super Mario 64, the first platforming game to remove that ability too, but it's not like there's more than one Mario anyway in the series). There's a plethora of choices to begin with. Shy Guy is one of my favorite options for a Yoshi character(Kamek being the other, but due to its weird naming issues where Magikoopa and Kameks aren't really different names in total, actually getting the specific Yoshi-related character is harder for people to get. Similar issue with Toad, but the original core one is more known than Kamek being separated from Maigkoopas. Also worth noting Toad has a different color set for the main one, while Kamek and the Magikoopa race are identical. I'm aware Yoshi is the same way, but he was separately playable in his own game, so it's easier to tell it's a particular person in comparison).