Fabs,
I too have never used my rangefinder to shotgun hunt deer as there just hasn't been a need to because almost all of my shots have been under 50 yards.
The rangefinder is a useful tool for bowhunting though, especially if you are hunting on an unfamiliar piece of land and you want to ensure that the correct pin is used on game that crosses ranged landmarks. Could you hunt without one? Sure you can but let's face it, alot of hunting is about confidence in your shot and preparation.
In the heat of the moment, I'd personally rather be certain that the monster buck with a body like an Angus steer and sporting headgear like a laundry rack made out of PVC I was coming to full-draw on, was already ranged at 35 yards from my vantage-point 20' up a tree so I know immediately what pin to set on him.
Of course, one could then make the arguement that one HAS to have a new whiz-bang pendulum site etc, etc.
To each his own...I suppose that without the advancement of technology the woods would still be filled with only flintlocks and stickbows and wouldn't that make for a simple HC forum???