People will pay what they want to pay, and what they feel it's worth.
Sellers will charge what they want to get for a piece of equipment.
Deals are made when the two come to an agreeable price point during the "song and dance".

If resale values due to cosmetic condition of your equipment get in the way of you making pictures w/ your equipment, sell it and don't look back.

I used to be the same way. I didn't get out enough to make pictures. I finally realized that if I got out there, made photographs(what the equipment was designed for), then I really didn't care what I paid(as long as I could afford it at the time). Of course, if I can/could find a "deal"(compared to going rates for other sales of the same model), then great. It makes getting a new tool less expensive. Rather than buying "pretty" equipment, I purchased equipment that had seen use, had scuffs and some dings, but still worked as intended. That way, I couldn't tell when/if I made a new mark. As long as it works as-intended, I frankly don't care anymore. Guess what? I can breathe much easier now !

If you're worried about putting a scuff on your camera because it might hurt the resale value, then give up now, because you'll drive yourself insane. I was driving myself insane before coming to a "moment of clarity" myself.

Use what works for you, and don't worry about what others use/why they use it. They're YOUR photographs, and it's YOUR equipment.