You can see the same type of wear in this picture I took August 2025:
Zoom all the way in and look at Esc and Shift.
My keyboard has worn a lot more since. I might send a picture of it later. If anything, I wish it would wear faster, because ClockworkPi never made alternate silicone keyboard covers and I always wanted a translucent one. I’d go ahead with some sandpaper but when I was 16 doing that with my Thinkpad T420 keyboard made it look uneven and a little ugly.