Easier to pedal in circular motion for more efficiency. (can still be done with practice...sans pulling up)
Shred gnarly hills with more confidence b/c your feet don't come off your pedals when you're bouncing around. (five ten's and some knobbly flats help alot though)
You can use poor technique and still hop over logs.
With practice and patience, you can tear it up with some good flats...clips are sorta the easy way out.