Yeah LST definitely helps with yield and getting more quality type main colas. With that being said my biggest two plants were not LST'd (Sour Stomper X Skywalker and SODK X Fantasmo Express both about 11oz) but I imagine if I had LST'd I would have had a few more ounces easily.
Main reason I LST'd is because it's more enjoyable (debatable I guess) and the tall girls just lacked light penetration at the lowers. Went from fluff to no fluff or little fluff by LSTing. One factor is you'll need wider space as they get bushier so it's not for everyones space depending on plant size.