1. Requires data connection, either WiFi or mobile data. SMS does not.
2. On Android, it goes through Google Messages. I don't trust Google.
So, I replaced Messages with another SMS app that doesn't spy on me and disabled RCS. If I wanted to do rich messaging through data connection, I would use Signal or similar.
So, RCS is not a replacement for SMS. It's just another IM protocol. And we have enough of those.
As for others replying through RCS, that's a failure of the messaging app, should recognize that the counterpart is SMS and reply in SMS. It's an attempt to force RCS...
SMS is for fast short messaging between mobile users, and that is its killer feature, it's universal. Every mobile phone supports it.
Signal dropping SMS support makes no difference for me, never used it for SMS, I used Signal for the secure conversations. Two different methods of contact.
2. That's not a requirement even though Google does their best to kill all alternative implementations. (Samsung had one, but Google paid them a lot of money to get rid of it. I have to admit I don't know who is left with their own RCS client)
> So, RCS is not a replacement for SMS.
It's 100% a replacement to SMS, it's literally defined in the same spec as SMS over LTE, as an upgrade to SMS. Though yeah Google made it, this... uh... thing. RCS is technically a federated standard, but Google killed every part of the federation and some parts of the standard.