I bought a pair of these some time back for use when car camping. The TNF Nebula has good headroom and porch space but it's not big enough to fit people sitting on folding stools into. So these were a good solution. With the purchase of a Therm-a-rest NeoAir a few years ago the chair kits fell out of use.
Until, that was, someone mentioned that they had been using theirs with their NeoAir. I lost no time scrabbling about the attic looking for them. And as the picture shows you can indeed use a NeoAir. The NeoAir is slightly wider than the kit but it still fits, all you need to do is semi inflate and squeeze into place, remembering to put the valve in the right place should you need to add some more puff - job done. At 300g I would never consider taking one backpacking, however if a trip comes around and we don't have the luxury of a pub to spend the evening in then I may do. Especially if that trip is in the winter.