When you're in a proper campground and have a site to yourself, you'll probably have a picnic table at your disposal. If you're rallying, though, or wild camping, you might want something other than your bike to sit on at the end of the day. This style of chair folds up and packs small enough to fit easily into any motorcycle saddle bag.
Helinox apparently did not patent their chair thoroughly enough, though, because just after their incredible success came a raft of strikingly similar competitors. The knockoffs are sometimes good, and sometimes very rickety.