Racing vs Cruising Sails ??
Truly there is no such animal as the two 'types' of sails. Sails come in Good, Better, and Best. The best designed sails made from the least stretchy material perform the best under wider wind conditions and as a result are faster, point higher, and heel the least amount, sure because they are more efficient. The others sacrifice efficient design and quality of material for the sake of price. A true sailor wants the best performance out of his sails, otherwise why bother sailing. The difference is racing sailors are not willing to give up the performance, cruisers are for the sake of price. Dacron sails will not last forever. They wont even last a few years where shape is the deciding factor. Sure you can continue to use them, you can also drive on bald tires. Bald tires work, the car moves but that's about it.