The Graceful Clothes are actually a little bit more complicated than that. They give the wearer 2 dex, but also limit the dex armour bonus to +2. So an attack and damage bonus for monks, but an AC penalty.
Depends on the monk's WIS score, as their Unarmored Defense feature adds their WIS bonus and their DEX bonus to AC. So for monks not focusing on DEX it's highly effective.
All in all I think there are way too many magic items, especially powerful ones. I just hope the game isn't balanced to strongly around them, as I have little to no inclination to use them.
