RCS is definitely convenient, but aside from limited availability, one key area where it lags behind instant messaging services like WhatsApp and Telegram is support for end-to-encryption as a privacy measure. But it appears that the Google Messages app will soon enable end-to-end encryption for RCS messages.
The latest build of Google Messages (v6.2.031) app contains strings in its code that hint at the arrival of end-to-end encryption for RCS messages. The strings make it clear that users can send end-to-end encrypted RCS messages, but in case their connection is poor, they can fall back to the legacy SMS or MMS standard.
However, SMS or MMS won’t be end-to-end encrypted. Aside from text and media, users will also be able to able to send their location via an end-to-end encrypted message. But these findings come from strings spotted in the code, so they may or may not be implemented in the future, something that is subject to a lot of technical parameters.