Also, because getting awesome work done with jQuery is far easier for the seasoned professional than messing around with plain Javascript DOM traversal.

Of course, you still have to use native JS functions for a lot of stuff, so you're not taking a shortcut around JS. You're just skipping the parts that are time-consuming, awkward, and inconsistent across browsers, and getting right to the useful stuff: shorter, more powerful, more expressive code.

Or is that just 'for beginners'?