I'd rather not have the blades extend from my wrist. Imagine the pain.
Edgy emo teens would rejoice.
With wrist blades, you get more application of force. You can slash and puncture. But finger blades would only work well for slashing. And here's the other thing.Imagine if you went to hit something with your finger blades, like armour, and they didn't puncture, and instead, you snapped you fingers? The wrist is a hell of a lot more of a secure location for them because as I said, you get more force put into your blows, where spindly finger blades don't, meaning they can be blocked easier and their source can be broken or twisted, much, much easier.
Seeing as I'm not a crime fighting nutjub in tights, the finger blades would be more practical for typical, daily use, such as cutting food, climbing things, or easily unhooking a chick's bra.
SpoilerElbows.Yes. More stable and you "punch" them to death.