Sure they can. The inside of the case is neither leather nor silicone. Also, cases are hard and fit tight to the phone.
At the time of reselling to exchange for a new iPhone it gives better value if you keep your phone in a good condition. That’s the only reason.
I also use the apple silicone case, on the contrary’s that’s the only case that doesn’t scratch the phone as their is microfibre lining on the sides as well. But it’s a lint magnet and I have got fed up of wiping the screen.
That lint that gets in the micro-fiber attracts also dust particles which do scratch your phone. Several threads here document that.
Funny looking at older iPhones from the time it was very common people had cases with a cutout for the . Looking at them now without their cases there’s often a ring of dirty scuffs around it, bet they didn’t expect that. In general I think it’s somewhat entertaining thinking about people babying their iPhone, putting it in a clunky and ugly case the hour they get it, never get it out and then one day realise how dust scratched their phone all the time while they thought it would remain pristine.
