Well, I can't speak for anyone else, but I know that I also prefer to use a closed bridge when shooting long draw shots. I believe it creates more stability to the stroke...so there is less room for error. Using an open bridge, the cue could come off the bridge and create a miscue if the players doesn't use a smooth stroke. With a closed bridge, the player might still use a poor stroke, but the loop keeps the cue pretty much in line...which reduces the chance for error.
Snooker players all shoot with an open bridge....even when they come to the US to live and play 9-ball. But I noticed about a year ago that Karen Corr switched to a closed bridge when shooting long draw shots. I can only assume that she did so for the reasons I mentioned above.
I can also shoot a long draw with an open bridge....but I choose the closed bridge because I feel more secure doing so.
Melissa