the idea of run linux as a user is to keep system as safe as possible by not providing excessive privileges to normal user
when you are logged as root you have full access to the system and you can do inadvertently or accidentally modifications to files that can comprise the security of the system
when you need to install apps, you should provide the root password, when you want to configure your pc, you should provide the root password, that is the idea of use linux, keep system as secure as possible
some apps won't work when logged as admin if i remember correctly
not much reasons to work as a system administrator afik