I'm not in the US but I use WhatsApp and android and thought it was some kind of iPhone SMS thing.
Is SMS in the US different from other countries?
The fragmentation isn't ideal, but it's better than the vendor locking.
Thanks for clarifying.
There's stuff like Beeper that allows for consolidation of multiple services, if you don't like having to use multiple apps for different people.
The difference is that in most other countries people don't use SMS to talk to other people; receiving SMS messages from automated systems is AFAIK still very common everywhere.
None of my family members understand that iMessage isn't just SMS.
I'm between the UK and Australia, and haven't received an iMessage in years, literally. I get SMS on a daily/weekly basis for 2FA things.
It probably has something to do with the fact that outside the US, iPhone market penetration is low, so it's assumed that sending someone an SMS will be an actual SMS, not always upgraded to iMessage.