Why don't you try it and judge for yourself?
Me, it takes too much energy to always hit a topspin backhand, and while you can slice off the same grip, it needs to be taken very early, something which doesn't seem to happen on every ball during a match.
My best biting slices or hit very late with a conti grip shaded towards eastern FOREhand, so it's a hard slice taken late.
Quite the change to try to hit early with topspin, well out in front of yourself. Too much change in strikezone for my feeble mind to embrace.