I mean, I've bricked plenty of installs before I knew what I was doing more. I still regularly see, in certain places, people give purposefully destructive commands. rm -rf / doesn't work directly anymore, but it'll work on your home folder for example. You also don't need CLI to install games, I would say literally never.

If a good third-party launcher that needed to be run as a system package showed up, Bazzite would just add that. Games that just ship a Linux executable like a lot of itch.io stuff generally works regardless and doesn't need the CLI. Can you give an example of a gaming usecase that requires sudo apt?

You can also install packages to the system on Bazzite by the way. It's atomic, not actually immutable. It's just frowned upon because it makes things less stable, and increases the length of updates. You use sudo rpm-ostree install in the same way, and it layers the package on top of the current version. It's treated as an absolute last resort, but it is way easier to reset to the base image if anything goes wrong.