Unique lock, blade shape and of course the full flat grind. Not really. That's usually what I dish out money for; interesting or strong locks, and/or more practical, better slicing blades. I'll be grabbing the Tatanka at some point personally. However, I carry an Avispa every single day while leaving my more expensive knives at the house. It has yet to get dull enough in a full day of cutting for me to justify buying any more expensive, less efficient knives.
Performance wise, there is no reason to pay more for designs that function as expensive bricks. In terms of collecting, bragging rights, or OCD issues over components and workings of a knife(we all have em), then sure.