I haven't stalked enough to vote, never even used a high seat, but they seem a good idea. If ground is flat or you have a place where Deer pass very regularly it's a good plan I think, saves walking!
I'm not lazy, but if you're still you have less chance of being spotted. It's a lot easier to let a Deer walk into you than try to walk into a Deer. Whoever is moving has the most chance of being spotted, so if you're still and the Deer is walking that has to be an advantage?