I picked one up for airgun hunting & pest control -- Sig Sauer. A 1" target and a scope rise of 2" over the bore makes for some close-range challenges. But when hunting (airgun & bow), like others, I may use it just to check distances at various landmarks as I'm getting set up. It also helps when I'm with my son (turkey, small game) so we can discuss when he is clear to take a shot. I'm usually pretty close in my guesses. But usually isn't the same as always.
That being said, I rarely use it for big game. I can usually tell if I'm within 20 yards for bowhunting. And a few reference points on my rifle scope is all the rangefinding I need to do for deer to tell me if I'm within 200 yards (my personal limit). An 8" vital area offers a lot more room for error than a 1" (small game) or 4" (turkey) vital area.