Marks like that on a "Working Tool" are what I like to refer to as "Character Marks." They show that a tool is being used, and is a solid, reliable tool that doesn't lead a mamby pamby existence on the shelf somewhere.
And, being aluminum, the anodizing is really decorative more than anything else. It's not there to protect a carbon steel from rusting, so other than aesthetics, it isn't really posing any threat to the tool.
Wear 'em in good health!
Def