Also the system files aren’t really the most important files. While it’s a pain in the ass, you can reinstall your OS and get that all back again.
Reinstalling all of your games is going to take more time, and if you lost a save file, well you’re never getting that back. Personal photos, videos, etc. are even a bigger priority.
So I tend to to think of the drive /home is mounted on to be the “primary drive” as it’s the most important. The root is just the system files, needed for the OS, but not nearly as important as /home.