Yeah, I wondered maybe if its because daggers would be too strong in that case... But even with those gloves, swords still do more damage in the end for sneak attacks. I calculated if I had the DB gloves, I would do almost 400 more damage with my swords of same quality as my daggers because I have one hand perks and one hand enchants.
Who cares when a dagger sneak attack already kills anything in the game...
Not to mention a dual wield dagger power sneak attack.
And daggers didnt make any noise unlike other onehanded weapons.