Using the clutch gives you "more juice". You run at a pace where you would normally have the engine at 3-4000 rpms, but rev it to about 8000 in the best part of the powerband, then use the clutch to get that power to the rear wheel.
The best part of using the clutch is that if you need more power, you can slip it some more to let the engine rev up. If you have too much power, you can slip it to release the power. I don't do this on my Ducati, but learned the trick on dirt bikes while hill climbing. (You bog down, slip the clutch for more power. The front end is coming up, slip the clutch to reduce power to the wheel.)