For me, it's not a blue bubble as much as the higher quality images/videos, compared to SMS/MMS. Trying to figure out which proper app a certain person has/uses, and remembering which to open for a certain person, is a huge pain. The full Beeper app is like old school Trillian: a bunch of clients in one. I just see messages from people. It's great!

I'm really surprised people still pretend they don't know it's not only about the bubble color

It's the images, videos and most of all, this the group chats. Being the only person on Android sucks if everyone else is on a group chat.