In my opinion, musicians should use backing tracks only if they REALLY need to. It's true that every day it's more difficult to find venues that are willing to pay for a band, and that it's sad; but I've seen entire "orchestras" "playing" their unplugged instruments over backing tracks just because they thought it sounded better (and because it was "easier", of course), and that's still worse. This is, in fact, very sad.