I have a bunch of apps that would not work correctly or work at all without root, e.g., Titanium Backup (or just anything that back up app data,) CallRecorder, Delayed Lock, Radio Reconnect (to MetroPCS that keeps dropping 4G signal in various places,) network speed booster, etc.
Also, ad blockers have to use root access. I'm being bombarded by ads without root at the moment. So yeah, even if you do not do hard rooting activities like flashing and theming, blocking ads is a good enough reason to get rooted.