I use them for yummy fabrics (upholstery, decorator, drapery, etc.) with which I make handbags. They are particularly beautiful, especially if nicely quilted before construction. AND they wear like iron! I do use a topstitch needle as it's a bit sharper and have no trouble whatsoever, even with multiple layers on a fold, etc.
As to the Fabric Wholesale Direct as a dealer, I could not be more pleased. They are fast, accurate and efficient. All products I've ordered are even better than I expected. They're A-1 in my book!