It's pushing these marginal edges that turns a profit. You're not expecting to actually earn $1.6 on a $100 investment, but the odds are dictating that you will usually lose less than your potential win amount.

At any rate, if I'm playing with my entire bankroll, I'd have to think about it....

but you usually shoulnd't be playing with a gigantamous portion of your bankroll, so this shouldn't be a problem.