Yes, that design has been around for a while... Personally, I wouldn't consider it (and I own SEVERAL different backcountry chairs) because it seems to have the worst of all worlds. You're basically sitting/lying on the floor with no padding (just a a strip of nylon under you) and the back is so low, that you can't really "sit".
Unlike many other backcountry chairs, you couldn't operate a stove while sitting in it (not without doing gymnastics), you're not off the (damp) ground, etc..
I think I'd rather just sit on my ground cloth and lean back on my pack (0 added ounces!), which would be just a tad more comfortable than this chair.
Of course, I really can't speak to its use as a sniper support...