How many times have you been impressed with a musicians technique, skill and creativity, but leave the performance not being able to recall the tune enough to hum it or whistle it. In my humble opinion, a tune should be understandable to the audience for it to be worth the effort.
Lets go back through time to some significant musical figures and see what they say.
They'd fiddle and fiddle and do all kind of stunts and never get nowhere. Nothing goes but old-fashioned fiddlin'. Just pure elbow grease and awkwardness and the tune that gets into your feet. I figure that any tune that will let a man keep his feet still ain't worth the playing. I don't write many instrumentals because they are so hard to do and they are so easily forgotten.