ORIGINAL: C-WOODS-SHOOT
As far as these "one pin out to thirty yards" people go, when I was heavy into 3-D and shooting 295 fps second there was always a difference from 10 to 20 and from 20 to 30. When I'm shooting at a dot, 11 ring , or a tuft of hair on the side of a deer that is exactly where I want to hit. Not an inch or two high or low.
This is one of the main reasons I use it. A lot of things can happen in bowhunting. The deer can move, the wind can gust, that little branch you didn't see can reach out and grab your arrow, and more. So if I know exactly where I should expect to hit and something does happen there is more margin for the other things that can happen. And if I bury the arrow right where I put the pin, all the better.
As far as only shooting 20 yards and in, that is a personal choice. I know my limitations are far beyond that, but I don't push it too far because of the reasons above. On the other hand, I am not going to limit myself to short shots for no reason because there is always that perfect chance that could happen and I want to be ready for it.
Of all the gear I could trim back on that I take with me, my rangefinder would be one of the last things I'd leave behind.