They are useful in the early game until a better set of gauntlets is found. Keep in mind that unidentified they are indistinguishable from gauntlets of peace. The only way to be sure about gauntlets is to identify them first. However, if humanoid monster picks and equips them, they autocursing nature is revealed. Thus, luring some kobold or goblin over unID gauntlets can be useful.
Cursed gloves/gauntlets do not allow to equip/unequip rings.
Gauntlets can be obtained in the same manner as all generic loot. Ratling duelists always drop gauntlets, which are never gauntlets of peace and can have higher than average armor boni.