The traveler does not affect sail shape. That is the whole point! The traveler allows you to adjust the angle of the sail without affecting the shape of the sail. Even a short traveler is better than no traveler. Use it when you can!
Yes, poor choice of words. I should have said 6 lines to CONTROL
the main. But I think you get my point. And at the risk of generalizing, most casual sailors really don't *get* what a traveler does or how it's used.