I think the petroleum argument may be valid if you’re using that leader years later. It’s not degrading the leader over the course of a day or multi-day trip. Burts bees has no petroleum and since that’s what my daughters buy, that’s what I use. You can always wash off the chapstick if that’s the brand you choose.Negatory on the chap stick, it is a petrolium based product that will eventually weaken the line and it can cause knots to slip. These are sort of non issues as most of it gets washed off. Spit or water for me, let it dry and then loon knot sense, plio bond or super glue. Don't coat anything but the knot with the super glue as it will weaken it if on the line (negates stretch or something not good). I read that the Knot sens adds 1% extra strength I don't know as I haven't tested it' I use it to help knots go through the guides more easily even if the only time this is an issue is when you string up the rod.
If using lip balm makes a smoother, burn-free knot, it’s probably a good practice.