For use when you are there maybe.......but portable space heaters are responsible for many garage/house fires. I'm sure the fire department members/retirees would know more then me though about safety concerns around gas tanks and other flammable things.
Food for thought, about climate controlled garages is that for those who warm their garages and then park a car or truck that is a daily driver in snow season they may be speeding up corrosion of the underside of their car and assorted fuel, brake lines etc. since road salts and moisture collect underneath then melt once inside. Only way to avoid that would be to wash the underside of the vehicle frequently even in the winter. (I don't see most people doing that in reality.)
I guess for long term storage for bike riders in climate control would not be an issue?