Brake pads "scratch" the rims. I never understood hard anodization of rims, they all go "bald" at some time, and the coefficient of friction between brake pads and anodized alumium is probably less than on bare aluminum.
Rims are the disc of the brake, and are worn in the same manner.
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If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.