No. Just some settings, like alarms in the clock app, notifications, location services, etc. All will need to be reset. You won't lose anything though.
Why do you need to Reset All Settings?
NOTE: "Erase All Content and Settings" will wipe your phone, and you will lose data and stuff.
I need to reset it because my Front camera is currently not working, and I searched up yesterday that it will fix the problem, and my phone is getting slow