I resisted singlespeed for a bit when most of my mates converted for the winter but 7 years in it seems odd to ride off road any other way and I now own 4 of them if you count the commuter. Twentyfour12, Mayhem, Dusk til Dawn, I’ve done them all SS and can’t see that my results would have been any better with gears.
If I want to ride geared off road I can swap the wheel, mech and shifter from my full-suss (which only ever gets used for uplift days). But that’s only happened once so far and I soon wondered why I bothered.