I've heard two suggestions regarding wax... 1. put it on your line-cutter to avoid rust 2. put it on your lines to avoid wear.

Dripping wax onto the line-cutter seems fine... hint: I just took mine apart - probably better to not do that. Pain in the ass re-assembling. Better to rinse it well; make sure it's dry, and just drip wax onto the metal parts and into screw holes. Parrafin / petroleum-based wax might absorb less water than beeswax, but haven't looked it up.

On the lines, I am thinking on the thicker braided portions - but I have concern that it might cause sand to stick to the wax, which might make wear worse! Main lines aren't rubbing things that are wearing them; it's more about stretch/shrink or abrading them on rocks or other line tangles.

You def don't need to wax your flying lines and doing it will definitely make matters worse. There is a product I've used thats really good for restoring the factory finish on lines and its called PrimeLines
www.kitepower.com.au/collections/parts-repair/products/primelines?variant=42348276751