The short of it is group chats lose functionality when even 1 non-apple user joins, and apple works hard to make sure you can't use imessage on other devices.

It's so frustrating. I want to like apple and their approach to privacy, but then they do stuff like this that alienates non-apple users.

Anyway, imessage is like a caveman compared to messaging apps like Kakaotalk and LINE. Those have more features and I like group chats on them much more than I do on imessage. Not that I had a choice; I don't think I ever got my Korean friends' actual numbers because everyone uses Kakaotalk.

[0]: https://www.androidauthority.com/green-bubble-phenomenon-102...

Besides all the other reasons already mentioned, its security model is somewhat dated. For example, it does not use forward secrecy, neither for chats nor for 1:1 calls. (Group calls do have forward secrecy.)

That said, I still use it over Signal when I can – cross-device messaging is very hard, UX wise (which device receives the notification, does "mark as read" properly sync across device, how is the behavior of a device coming back online after a while etc.), and Apple has almost perfected it at this point.

1) No disappearing messages 2) your messages sent to other people get backed up to their icloud 3) no cross platform support

#1 being the most important to me.

For one, it happens to be a walled garden.

Because it's ios only?