I don't really get this. There has literally been one Ditto who transformed like this, and it was in a single episode in the anime. On top of that, this issue had been resolved in that very same episode
So, how did this idea spawn that this is what Ditto transformations look like?
I don't think it's the idea that all Ditto transformations are like this. It's just more like a "what if" scenario of what is the "ditto" transformed into all these other pokemon. This is obviously a way for Nintendo to sell more toys. But these "ditto" versions are awesome, as plain Ditto is rather plain and boring. The "ditto" balbasaur is still my favorite, he looks hilariously great.
Also it's considered funny and cute, and the Japanese love cute things.
Yes, very true. I can understand why this merchandise exists (especially since a proper Ditto transformation is indistinguishable from the original) and I like it a lot too!
I just see a lot of people think that this is what an actual, proper Ditto transformation looks like. (Well, at least back when I dabbled in Pokémon a bit more than I do now; nowadays, I don't really visit any Pokémon discussion forums.) And I simply fear that this sort of merchandise only perpetuates that misconception