The elimination of cogging has probably already been covered here. But I also found another advantage on my Losi Truggy. The "direct drive" spur/pinion made my 1515/1y run hotter probably due to the load on the motor to get the larger truggys moving from a dead stop. With the clutch, you can get the rpm up on the motor before it is "loaded" up. On a side note, I put a really small outrunner( that had no business being in there) in my 8ight-T, spur/pinion it would overheat the motor and ESC right away. With the clutch, I ran an entire 5000 mah pack and the motor never went above 90 degrees and the ESC ran about 120-125.

So, would the clutch allow for more motor options?