No sawdust isn't a good footing. It breaks down fast when stepped on and becomes dusty. I love the new wax coated sands that are out there, and stone-dust with a dirt/sand on top is great, but needs to be watered :(
I have only seen sawdust used in stalls and aisle ways. We have dirt/sand and they tractor it every so often when it gets too hard. We did at one point have wood chips for the indoor, I hated them, sand is much better and softer!!!