Doesn't backgammon lose a lot of its appeal if you're not playing for money? Kinda like poker.
Also, in backgammon, you still need to actually win. Contrast this with poker, where oftentimes when playing for money, you don't actually want to reach the end of the hand (i.e. showdown). Which, again, is pointless if there's no money involved since always calling is your optimal strategy.