Not the color I would have chosen given a choice, but they were on sale and all in this color. The various box pictures show people cuddled up reading, watching TV, or playing board games, and even suggests you could take them to an outdoor sporting event.
However, as the back is completely open, I think this last is a tad unlikely. No point having a toasty front if your back is still exposed to the inclement elements.
The Snuggie is in fact just a 6' x 3' rectangular blanket with arms sewn in. Mine is made from microfleece material. However it is very cosy, and the boots are warmer than slippers as they keep my ankles warm.