It won't detract from the look of the boots/shoes if done right. There is a proper way of doing it, by removing a layer of the sole and placing a rubber piece in there of the same height then shaving it off and painting the midsole (not sharpie) so that it looks flawless. It's those small details and proper way of doing it that makes a difference. As for benefits, no more sliding around and crack your head on the pavement when you slip? It's much more comfortable with the rubber sole? Though there are some debate on it, I am on the side that topy does make shoes last longer (especially on the toe and heels which deteriorate faster, metal toe or heel taps works too). Honestly, just the traction is enough of a reason for me, I walk in too many building with marble floors that is just waiting for my ass to land on them.