I bought the smaller one last year and outfitted it with a chuck and coil hose and a tire inflator with guage on it. It take it with me when mowing at remote grass cutting sites in case I get a flat on the tractor. Also great for around the yard in case a tire goes flat.
I don't bother putting it in the Jeep though. Tank isn't big enough to make a difference in my 37" IROKS if one was flat.