Can add too, until it can send in almost any wireless situation like SMS can, it isn’t worth bothering with. SMS can send on LTE even when a phone doesn’t have a data connection available to the userspace. (Bars but no G icon.) It can send on 2G or above practically instantly. (Although once T-Mobile turns off 2G next year, less of a concern in the US.) SMS is just a raw simple control channel message. RCS is, as others mentioned, just another over-the-top messenger with all the network stack overhead, and a buggy one.
One can fire off an emergency SMS on the side of a mountain with barely usable signal that won’t even work for a voice call. RCS would fail in such an environment.
MMS, of course, requires a carrier APN data connection to work, and is a bit slower and more finicky. RCS would definitely be an improvement there.
LLMs are really fucking bad at math. They’re trying to find the statistical close answer, not doing computation. It’s rather mind-numbingly dumb.