RCS isn’t encrypted though, whereas WhatsApp is. I can use WhatsApp with anyone in the world, it’s compatible with basically any carrier network in any country and any phone. It’s not clear what benefit you’re saying RCS will have over it?
Nope. WhatsApp requires an Android, IOS, or Windows smartphone. WhatsApp is not a protocol you can freely implement, its a piece of proprietary software you have to install. No third-party clients.
Your carrier just provides you access to the SMS/RCS network, they have no control what software you use to access it.
I still use SMS almost exclusively for the simple reason that it is standard—except for group messages, for which I use Signal.
I can only speak as an American, but sending an SMS to Europe costs 20¢ on my plan. Hardly astronomical, especially considering that when SMS was new, it cost 50¢-$1.00 per message.
I might have sent 100 short messages just to my mother this month. That would be $20 just for talking to one person. Last time I had a UK phone contract I was paying £13 for unlimited data.
Yes, 20 cents is astronomical.
I wouldn’t dream of communicating the same way if messages weren’t “free” (i.e. part of your internet fee)
I say this as someone with “most of my friends” living in other countries at any given time.