RCS is definitely practical, but apart from limited availability, end-to-encryption support as a data protection measure is an important area where it lags behind instant messaging services such as WhatsApp and Telegram. However, it appears that the Google Messages app will soon enable end-to-end encryption for RCS messages.
The latest version of the Google Messages app (v6.2.031) contains strings in its code that indicate end-to-end encryption for RCS messages. The strings make it clear that users can send encrypted RCS messages end to end. However, if their connection is poor, they can fall back on the old SMS or MMS standard.
SMS or MMS but not end-to-end encrypted. In addition to text and media, users can also send their location via a consistently encrypted message. However, these insights come from strings contained in the code, so they may or may not be implemented in the future, which is subject to many technical parameters.