I have a coffee table height desk integrated into my loft space where I'll often use my laptop while seated on the loft's floor.

It's actually more annoying than just having the laptop on the floor and leaning my chest forward against a bent up knee.

But it is a nice option for variety sake, and in my setup it's also the orientation required to enjoy the windowed view outside. In terms of pure ergonomics and computing comfort though, it's not as good as just the floor.

There's also the whole multihead display thing that the low desk provides, it's always a compromise.