Does anybody know for what purpose the Silken Gloves serves ?

There are many things with negative effects in the game and neither one serves any purpose.

There are a few things with only negative effects that can be sold, but are useless otherwise.

However, there are a lot of 'mixed blessing' items. Things that have negative and positive effects.
For example, some of the most powerful weapons are cursed. Some have an additional HP or SP drain, but are great if you can live with it.
Another example is Pucks Cap (IIRC; the item with +10 music, but bad other stats). Its quite useless, unless you want to drag Saxx into areas where he doesn't want to go. With the cap, he has still the 85 music required for the most powerful instruments.

Yeah, like werebore said....
I found a ring last night that added 20 to stealth and 10 to speed but it had a negative 1 to stamina. My faerie ninja was walking around unconcious for a while and at the beginning of every battle I had to cast stamina on her so she could get into the fight. But its worth it...especially since I found her a +1 stamina amulet.

Sorry that's WereBOAR...not what I typed ealier. Really sorry, it was just a typo.