It depends upon what you're going to use it for. From the website, it looks like the intended use is as a groundcloth. It's small for a blanket, but I guess it would do in a pinch, though I wouldn't count on much heat retention if used as a blanket in a cold climate. I think I would use it like a tarp, for rain protection or as a sun screen. I did order one, just because!
During the winter months I generally carry a goretex bivy sack, which can be used as a lightweight sleeping sack, plus keep you dry too. In the summer months I've camped with just a bivy sack and a tarp. One of my bivy sacks has an insect screen around the top, so you can keep your head out without getting chewed up by bugs.