It is a controllable skill that is to say, it will not level up by accident, other than by reading books, so it makes an excellent Major or Minor skill for those that want to maximize Attribute gain, assuming the player wants to use it at all. It is vital to keeping weapons and armor in top condition, where their effectiveness depends to a large extent on their condition.
Higher strength will improve success in using it, and gaining levels in it will count towards Strength Attribute gains at character levelup.