RCS is the modern version of SMS served over data/wifi. It improves security and allows you to group chat, send pictures/videos/voice notes for free without incurring MMS charges or having to use thi...
MSF no, one of the main benefits of RCS is not having to use a third party application to benefit from modern messaging features. This is a replacement/evolution of SMS, not an alternative to WhatsApp. Also, I personally don't trust or like Meta as a company.
This hasn't really dragged on at all. RCS for iOS only launched in the UK in November/December last year. If Smarty is a modern carrier, it should be perfectly capable of supporting RCS. The lack of communication is a tad concerning, though.