I actually like this idea, why not pair it up with armor?
When your armor is gone your armor literaly breaks in combat, your sword literaly breaks too.
I like that, maybe also ahve a normal durability but realy thats mostly so breaking down doors has some form of limitation.
Maybe Larian could add in code so that each time you save the game there's a 0.25% chance that it will format your hard drive. That sure would make the choice whether to save meaningful and exciting!