Seated Dumbbell Snatches

Has anyone ever done Seated Dumbbell Snatches?

This is the only video I can find of someone doing them at the moment. (He does them at 1:17)

There’s a video somewhere out there where some guys who are squatting pretty heavy also do some 100lb Seated Dumbbell Snatches , but unlike this guy their butts come off the bench and they ascend to a quarter squat before dropping back down on the bench.

It looks to me like the guy in this video is just ripping it back, and he’s pretty strong. He’s got a 300+ Axle Press on one of his videos and a 500lb Front Squat on another.

So, is this a legit exercise? What is it for? Would I do it in place of Shrugs or Seated Dumbbell Power Cleans? Would I do it on a Dynamic Effort Squat day instead of doing Box Jumps?