How much do I gain from switching to it instead of say, remaining on the Stock Android?
Edit: This looks comprehensive — https://staging.grapheneos.org/features
This is an OS for people who care more about privacy and security than having an everyday usable phone. It is very much not for normal people.
GrapheneOS is intended for everyone.
> It really only works well if you don't rely on any apps that depend on Google play, like steam or discord.
Steam, Discord and the vast majority of Android apps work perfectly on GrapheneOS. Sandboxed Google Play is a robust feature which works very well. If you're choosing to completely avoid using Google Play, that's your choice. Steam and Discord both still likely work without it, but without push notifications since they have no alternative to FCM as certain other apps do.
> If you're on AT&T, you don't get caller ID or voicemail.
You do get caller ID and voicemail on AT&T. Visual voicemail doesn't work with AT&T with the built-in Dialer app because it uses a protocol not supported by AOSP. It does work with Google Dialer based on user feedback on our forum.
> This is an OS for people who care more about privacy and security than having an everyday usable phone. It is very much not for normal people.
GrapheneOS is very usable as an every day usage phone for regular people. Nearly every Android app can be used on it. It sounds like you were choosing to use it without sandboxed Google Play, which is a choice to have a more limited app and service ecosystem. That's not the same as a choice to use GrapheneOS. It can be used like a regular Android phone with 1 profile containing sandboxed Google Play, or people can use sandboxed Google Play in a specific profile with most of their apps in another profile. Using it without sandboxed Google Play in a secondary profile is something many GrapheneOS users do successfully but it's in no way required or expected. We wouldn't have made that huge feature if we didn't want it to be used by a lot of people.