Homemade mono leaders rely on three to four separate knots, each one acting as a constant invitation to slime and more solid debris. Furled leaders taper smoothly from end to end, with no knots. No question that fishing a clean leader reduces drag, makes the leader less visible, and helps in executing the cast as well.
Handling a furled leader for the first time is a little strange. They're completely and uniformly limp, from the tippet all the way to the end of the butt section. This overall limpness allows for a smoother and more complete energy transfer during a cast. To be fair, many mono leaders allow for smooth power transfer, but furled leaders unfurl more evenly, increasing an angler's ability to deliver flies more delicately. Check back with the Trout University soon as I believe that I will be writing a new course on the subject.