Club Curling Question

I have been watching club curling for several years, now, and I took it up myself last year. Something puzzles me:

• Why do so many club curlers let go of the rock at least ten feet from the hog line?

I know they might be afraid of hogging the rock, but you don't have to let go that early to be safe. I also know that most of them are not "competitive" curlers (who continue to readjust the rock infinitesimally right up to the hogline). Why let go of it so soon?

Is it because they're too weak to push out that far? Too stiff and unstable to stay in the proper delivery position that long? What is the reason?

I use a push stick because I'm too weak, stiff, and scared to use a normal delivery; nevertheless I go right up to the hog line before I stop pushing the rock.