For low end performance is there any benefit using light weight racing kite lines?

Definitely, less drag and less weight. The Ozone Race lines built from SK99 dyneema are great, not so thin to be fragile but great for foiling.

Absolutely. I stocked up on a few sets of Ozone 200/100kg back when they still made them. If they all wear out I'll grudgingly go to the current Ozone 300/200 race lines but for riding with minimal kite size I'm finding the 200/100s last ages and perform sooooo much better than regular lines. Bring back the 200/100s please Ozone!