Perhaps because it is more than, say, Christian Bale yelling at the stoned kid in the back seat; these are real musical Mash-Ups, like the kind you would listen to on purpose, except using YouTube clips as source material:
Or really, the YouTube clips are instruments. The method, apparently: the guy peruses god knowsh how many clips of songs, historical performances, homemade bedroom noodling, high school band recitals, and low budget YouTube instrumental instructional videos, and combines them to form his own songs. The result is seven diverse -- and good! -- songs of various genres. That first one arranges some fairly active and original funk out of dozens of different instruments and melodies, including a guy with a mullet playing a theremin.
I also like Babylon Band, an unintentional ethnoelectronic supergroup with a levantine sound formed by combining a stonerish kid on his elaborate drum kit with greek teenager jamming on what looks like (to my untrained eyes) a tambouras: