Never felt the need to go fac air as my 12 fpe pcp handles anything out to 45 yards, my rimmie out to 75 yards and my .17hmr takes over beyond that range.
If I had land that needed more 'legs' than a legal limit air rifle, but less down range oomph than a rimfire, I guess I'd get fac air.
Remember that the hummer goes off with quite a crack, which can limit its uses.