Look up some alternative SMS clients on the Play Store and you will see there is a market for it. People on forums have been also complaining about there being no way to do this with RCS.
You wouldn't know how much demand there could be till you build it, iterate and innovate. You can't ever do that if regulations stifle it completely.
I don't care. But I'd rather live in a world where tinkerers can tinker away since I imagine they'll be able to make something I would care about later as a consumer.