Most of the time, those electronic backings sound about as thin as the soles on a pair of cardboard shoes, and just as cheap--the vocalist who use them, however good they may be, get swallowed up in the noise, and don't come off any better than the shoes--you do get consistancy, but it isn't the good kind-

Performing with a synthesized backup may be preferable to playing with a cold, drunk, house band, but that is hardly a desirable performance situation either--

Any instruments can be used to make great music, and originally, synthesizers were used to do great things, unfortunately, they are often used to create cut and paste music, which sounds enough like the real thing to pass for it in a noisy room full of drunks--when you really play a real instrument, repetition makes you better, but when you play a midi file, it never gets any better--