True. The if you hit something is the critical part. Ever seen a griz charge? It’s lightning fast, a few second at best and they’re on you. Unless you train for it routinely, you’re not likely to hit anything with your 1, maybe 2, shots from a .44 wheel gun. Especially the old men I see carrying them around here (SW Montana). Mag dumping a 15+1 10mm if the best way to save your hide.
Based on real world attacks, the loud noise and sudden pain from a handgun is enough to break off most grizzly attacks. Including 9mm handguns. Doesn’t kill them, but makes them change their mind.
If you meet a really determined grizzly or polar bear, a 375 H&H Magnum is about the smallest thing that counts.