I don't think it will increase yeil much...I just think it's another neat way to grow.......maybe if you can only grow in an attic or some other weirdly shaped space it would be perfect.
I would say no. Would help tomatoes cos they waste a lot of their growth energy growing by attaching to things to reach light. All this energy can be used else where since it is not growing up. Herb stands up by itself. But then again you gotta try it to judge.