The problems with teflon tape: First, if you are screwing a fitting into a somewhat fragile aluminum part, the teflon tape can cause the hole to expand so much that the aluminum cracks. Second, when you take a taped thing apart at some later date, you'll find that the tape has shredded and the little stringy pieces can be hard to remove. If that stuff makes its way into your fuel system, it's going to cause problems. It can ruin engines if ingested into to oiling system. The paste/liquid has neither of these problems.