Audio loops are a very simple technique to quickly lay down some background to play along with.  A very early audio looper was simply an electric guitar with an internal loop of tape to record and playback segments of a song, though similar techniques could be used to create delays, echos, and even a variety of flange and chorusing effects, but let's stick to simple loops with a few effects..

How to get funky in less than 2 minutes while being appropriately attired too ;)

This man is very talented.  I assume he's practiced performing this song using the loop pedal but still it's an excellent performance.

I assume it could be easy to get lost playing for hours with some of the machines.  This performance makes it look easy.

... now consider even longer loops, an ability to fade tracks in and out or occasionally randomly trigger new sections and  ... well, those are things that I believe a lot of musicians are fascinated with.