I use braided line to fluoro leader mainly on drop shot. Drop shot is a slow presentation. It has made a huge difference for me to have a fluoro leader. My set is braided line, a 2 feet of fluoro leader, a hook, a 2 feet of fluoro leader, and a pencil lead weight. The loop-to-loop knot that joined the braided to the leader does go into the first 2 guides of the rod and it does make a tiny little noise as it shooting out but it doesn't effect my casting at all.
Now if we're talking about faster presentation like a spinner bait, a crank bait, or a swim jig, I'm not sure if you need it. I've seen my buddy, Danny, fishes straight braided line to these lures on Lake Geneva and he has been doing well.