2 biggest reasons for holsters is: conveinence and security. With one holster you get convienence but not so much security. I once found a Model 66 on a Mountian trail a 100 miles from civilization that fell out of a non-secure rig and the owner never felt it leave his person.

I found this 66 4 miles from the trailhead. Never did find the owner. Betcha he wished he had purchased a holster that fit his weapon properly!