William Ronald
Explorer
Adventuring blacksmiths do not get a lot of time to practice their craft, so allowing them to gain some experience points by facing challenges and obstacles is a reasonable way to ensure some advancement. Over time, most of us get better at our various professions. In D&D terms, an expert blacksmith could gain most of his experience by working on his craft. Slaying monsters and rescuing captives might make the blacksmith popular. However, it really does not have anything to do with his profession.