Did this thing actually do anything special in-game? Like, I know alike Mew it had the gimmick of being the extra Pokemon you had to get by some outside means, but did it have any in-game gimmick, like Mew's compatibility with every TM/HM.

I didn't get Celebi back in the day, and I played each new game a bit less intensely than the last so I didn't pay much attention to the creatures I didn't catch, but I'm curious now, did any of the new "Mews" have an interest gimmick like the original did?