For those that are still not convinced about the loose footed main, I have been holding back with the ultimate clincher.
When the temperature has taken a tumble, and a driving rain is lashing at the sail, all the water comes roaring down that non-loose-footed sail (what is that called?) runs about half way back along the boom and dumps on the poor soul seated on the lee side of the cockpit. If that person happens to be a guest or crew, who cares. You can just let the person know that the bath is part of the thrills, the excitement, the love of sailing. But if you are seated there and get doused, or one of Commander Pete's friends is seated there, and decided not to go out on the boat again, what could have been an enjoyable romp in rough weather becomes a crisis.
On the other hand, with a loose footed main the water never gathers on the boom, but is blown away in fine droplets under the sail before the water reaches aft to the cockpit the cockpit. It is much therefore much less likely that your can of good German beer will be severely diluted with rain water.
Now that has to be worth something!