You don't even have to ask this English busker/artist/engineer why he made his pedal-driven, guitar-plucking, steampunk-looking musical whatsit, because his reasons are bolted to the side:
I built this machine because of unreliable guitarists. It don't smoke! It don't drink! And it's never late.
That's great, guy, but I've got a strange feeling that alcohol isn't completely out of the picture here. [CollegeHumor - Thanks, Reed!]