why is iMessage on Android such a big deal?

Being able to use rich chat features.

Like what? I know there is a difference in how group chats are handled, but thats a compatibility issue, not a rich chat feature. The only thing I can think of is Apples stupid push for more emojis and even worse Memojis. Otherwise, pics, gifs, emojis work between Apple and Android. Seems like its the green v blue and group chat edits that are the differences.

But maybe I dont know.