These are the only H2H weapons that MNK can use which have Slashing damage instead of Blunt Damage.
Unfortunately, WS's have their own special properties that don't care about what DMG property the weapon that you use has. That means that Asuran Fists, a blunt WS, will deal Blunt Damage even if you have these Slashing Claws equipped.
What it boils down to is that on blunt-resistant mobs such as Slimes and the like, use these but save TP for a blunt-neutral or blunt-weak target. (Hehe, I wonder if the Slimes figured out that too much blunt will make you resistant.) :P
Hopefully this clears up the reason why even 75MNK's might want a pair of these around "just in case". (For example, in the Limbus zone SW Apollyon, on the first floor.)
EDIT: Supposedly, Custodes also now deal Slashing damage.
Edited, Nov 11th 2009 7:37pm by NatePrawdzik