I find them horribly uncomfortable, unhygeinic as Doctor Spoon pointed out, and unsightly. If I were in a survival situation and needed a quick handle, I'd be much more inclined to pad it out with something else (tear a strip off a tshirt if possible, though i'm sure an alternative could be found) and then wrap it in paracord, but that'd really be a last resort for me.
Seeing as most of the paracord knives are NOT handled in a survival situation, I really don't understand why its used. Its ergonomics are nonexistant, generally ending in a handle that is (in my experience, and to my tastes) too thin and for the third time, it's unsafe as far as bacteria is concerned.
Not meaning to cause any offence, just offering my opinion
Peace!