You have protection. You got AppleCare+ with your phone right? Right?
Two incidents of Accidental Damage and Handling (ADH) at $49 each, no questions asked.
I hate cases, they ruin the look and there are some real fugly ones (Otterbox) that make your phone unrecognizable as an iPhone. But I don't resell my phones, I use them and enjoy them and then move on to the next when I can afford it and put the old one to a different use.
Most people wanting a pristine iPhone AND using a case to achieve that are doing it because they want to resell the phone to fund a new one. I don't play that game, especially when I have to hide my phone during the years I'm using it. When you have heart palpitations because your phone is out of your case for cleaning and it's all you can do to get it back into it's case – well it's time to rethink things.
My iPhone has been dropped, it has scratches and scuffs and one chamfered edge has been worn. But it's not beat up and it's fully functional. Use a case or not, it's personal preference.
I'd just rather enjoy seeing and using my phone without a case being in the way.