Like old school D&D.
It would be nice to have some kind of reason to equip a weapon at some point on a monk. Also you would think that a class that trains how to fight all their life, including with weapons, would do more damage with them...at least moderately comparable to no weapons at all.
And compared to carrying around kamas for 3 years and never using them.
It might be too powerful to have it for all weapons, it is certainly more powerful than say fighter weapon specialization, but given that handwraps would still be better, 'overpowered' is a relative term. It would be like giving a fighter +10 damage on their fists - sure it is a lot, but no one is going to fight with fists unless a monk anyway.
It could be say +1 damage per 3 levels maybe, would still be somewhat useful at least.