>>47060423It's honestly because of the consistent writefagging more than anything--though the new images are a pretty good reason, too. There's a whole lot to the idea of illusions; unlike Ditto, which can basically keep it up a real transformation as if it were effortless, the Zorua line has to keep up their illusions continuously, with any physical trauma or significant lapse in thought being enough to shatter them like cracked glass. They add tension in unusual circumstances.
There's also the fact that they can be used to hide something or someone for reasons unknown. A person so used to conjuring illusions could even be subconsciously using them all the time, just to make sure someone doesn't find out about one of their dirty secrets. On the flip side, they could also use their illusions so that the people they like see what they want to see. All in all, they're a really neat narrative tool that naturally lends itself to cool ideas for stories.
I guess I am being presumptuous about Dittos and Mews, though, since a proper writefag could make the concept of temporary transformations interesting through limitations similar to Zoroarks' illusions.