I don't really see that as abused... Steel can pick up a lot of "character" on the surface without affecting its strength to a significant degree. We have wood working tools that are over 100 years old and they are completely brown with age, and they still work great. The images shown actually look quite a bit like an old saw blade, they acquire that same combination of dull polish and specks of color. Buffing it mirror-shiny every time you use it sounds like you're taking off a lot of steel over the lifetime of the tool, in my opinion.

To me it just looks "well loved" as Rainwalker says. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />