RCS is an open standard that any carrier/OS/messaging app can support, unlike iMessage, which is exclusive to iPhones.
Using my phone number as an identifier and authentication factor for so many things these days is bad enough; I really don't want the messaging layer itself to touch my phone provider at all.
My preference would be that Apple drop SMS support from Messages all-together and market it as an iOS only communication method. People with iPhones would then have to pick some alternative, perhaps they would use Signal or perhaps something else.
I already have to install a handful of applications to talk to all of my friends and co-workers, at least I wouldn't have to continue to use SMS.
IMHO, RCS isn't a solution to anything since it still requires phone carriers to adopt it. A quick check of the internet indicates that many of these phone carriers are actually charging more to send RCS messages than SMS, making it a non-starter all around.
Maybe Google could create an iMessage-like (internet only) alternative for Android... Although it still wouldn't work with the actual Apple iMessage protocol unless Apple adopted it. IMHO they'd have better luck getting companies like Apple to interoperate if it was pre-installed and worked on all Android phones.