Also, you need tha .PAC with Sheik/Zelda/All Pokemons/Wario/Zero Suit Samus/Samus/Bowser/Forgot who else, why?
In case you play Sheik/Zelda, if you have the .PSC and not the .PAC, and you start the match as Zelda, you'll have the Texture, but once you change to Sheik:
> Sheik's Texture won't load.
> And once you turn back to Zelda, she won't load the Texture either.
With the .PAC, they'll be able to have the Texture even when transforming between them, same happens with the Pokemon Trainer, as for the rest:
Wherever you use the Final Smash for Samus/Zero Suit Samus, you swap between them, and the same that happens with Zelda/Sheik and pokemon Trainer will happen
As for Wario and Bowser, perhaps you didn't know but their Final Smashes (Wario Man and Giga Bowser) are considered as individual characters, it's easy to notice, so it's sorta a transformation, so the same happens)
I understand its use for transforming characters.. but why would characters like toon link (in the example) need the PAC file ?