Proper use of the Traveler
I use the traveler quite a bit. When I''m going to windward in light air I cheat the traveler up so as to get the boom over the center of the boat without having to sheet so hard that I lose sail shape. I also use it when falling off the wind a bit. I can keep the main sheeted in and travel down to keep the boom from rising and again help maintain sail shape. This is more important if you don''t have a boom vang.
The traveler simply allows you to keep your sail shape over a wider area than if the main sheet was in a fixed position.
Best of luck