SE needs to upgrade these like the Silence Dagger into a Hushed Dagger. If you could synth this into a "Pitch" Dagger or something to that extent, that granted the Enchantment of "Enblind" then maybe it would be more useful.
Since daggers don't seem to make much of a difference at lower levels, especially against Snippers in the dunes, Dual Wielding these make much more sense. However, why would you use Blind Daggers in a party? Black Mage can cast Blind easily. Solo these weapons suck.
As far as I'm concerned this weapon is useless. For me it proc'ed about once in every 4 or 5 fights, but when it did there was no difference in the fight. The monster hit me just as often and did just as much damage as before. It is pointless to even use this.