RCS is the long-overdue successor to SMS, but it has suffered from several holdbacks. Notably, Apple's opposition to supporting the standard in favor of its own iMessage service (which it uses as a selling point for its devices) has represented a notable setback for the objective of having the standard adopted by all mobile devices. Now, though, it looks like Google is going all in and enabling RCS for most Android phones — completely disregarding the issues that currently exist with it.
Google has announced that RCS is now officially enabled by default for new and existing eligible users who are already using the Google Messages app. The company has rolled out RCS for most countries and network providers by this point, and it's currently used by millions of people, so really, this is just Google flipping the switch on the few holdouts that currently exist. For most people, opening the Google Messages app for the first time will prompt you to enable it anyway. Now, this prompt won't be there — RCS messages will just work. If your carrier requires you to agree to certain terms of service first, you might still need to see a prompt and accept those terms, but other than that, it should be smooth sailing as far as messaging anyone on a modern Android phone goes.
While this might sound great, since traditional SMS has countless limitations, it's hard to be fully on board here. Notably, RCS is far from perfect, and it never seems to work quite right for a lot of people. While Google is flipping on the switch for everyone, it should also be prepared to fix many of these issues promptly, and it should also be ready to fix more issues were they to arise. Because bringing in a bunch of people, many of them without their knowledge, to a service is practically begging for something to go wrong. We will likely reach the point eventually where everything just works, but it will take some elbow grease to get there.
If you haven't turned on RCS, make sure to enter the Google Messages app and check your Settings to see if it's enabled.