I appreciate your interest in having the RCS supported on the native (Samsung) Messages app. At the moment, we are unable to comment on the service which we don't currently offer. Please stay tuned we will update the Community as the information becomes available.
From what I've read about RCS, Samsung's stock texting app is supposed to be inter-operable with Android Messages as they both support whats called the RCS "Universal Profile".
The Universal Profile is what Google is pushing and gaining traction with. Prior to the RCS UP, some carriers had and still have RCS but it isn't compatible with other RCS servers.
I'm pretty sure in the RCS whitepaper they mention Samsung's app client uses the UP.
Down the road / in the future, I have to imagine that other app makers will adopt RCS into their apps.
Features that Viber or WeChat or Textra have that are unique to their ecosystems will be coded into the RCS Universal Profile (server software), and any other app maker/competitor that wants to support those features can add them into their apps (client software).
Features such as 'stickers' and deleting messages sent as a mistake and 'Snaps' like what Snapchat does.
The whole benefit to the RCS UP is to get the carriers (Rogers/Bell/Telus) involved in Internet chatting... SMS/MMS is limited and not preferred these days. The bonus is that if someone you Chat with doesn't have a UP client app on their device (iPhone), then a regular SMS is sent in place of the RCS Chat message.
Google Hangouts did all of this and some more (with Google Voice in the USA) but was limited as it could not send SMS/MMS.
It's certainly a good news for those who love the Samsung Messages app. We don't have any new information to share about supporting RCS with the Samsung Messages yet. As always please stay tuned we will gladly share any updates.