The thing about the "solo guy with guitar" thing is that there is a finite amount of what he can do. With backing tracks there is not. Plus, the 4 beer fueled post above made a great point, that is another "I play with canned tracks" guy sits down to someone using canned tracks, we know what went into those tracks. Remember, the average listener thinks all we do is play those 2 or 3 one hour sets. No practice, no prep....