We went for decades using film cameras without having the ability to know how much they had been used, and nobody gave a rat's ---- about how many shots the used camera they were interested in had taken. If it was in good condition and worked then that was good enough.
Now people have latched on to the idea that a camera can apparently tell them how much use they have had and now 'mileage' is the thing to look at. Well, just like cars, cameras can be clocked too. The image number isn't necessarily an accurate record of the number of shots taken. And for the cameras which can have the true image count measured via software, how much longer before somebody cracks it so you can put whatever mileage you want on a camera?
I don't know if it's a good or bad thing. A camera that can be confirmed to have say 10,000 shots on it may still have years of life left in it. Yet the uninformed prospective buyer might think "That's not worth £300 with that many shots on it, I'll give you £150 for it".