That is one way of looking at it, but in the same vein I could say a mortgage interest rate is "an attempt to lure people into borrowing money". Depending on what he means by "a percentage" it probably is approximately one or other odds systems. I would say they are both commonly agreed metrics of a proposed contract.
On interpretation, in an efficient market they kind of are a prediction of the probability of an event. In the same way that one can calculate the metrics like
probability of default from borrowing costs we can interpret implied odds as predicted odds. To dispute that one could claim that the corporate funding market is more rational and efficient than the political betting market, which I am very far from convinced of.
An efficient market is as much a fantasyland as Narnia. When betting odds are first released, until the book has had time to adjust them, they could be taken as the book's best estimate about the likelihood of the various outcomes. This is just a means to an end, though. After money has started coming in on the two sides, the book adjusts the odds so that new bettors will continue to put money on both sides. Once that starts to happen, if we continue to use betting odds as a prediction of the outcome, we're relying on people who've placed bets being rational, expert, and objective. A smart gambler watches the odds change and places money when they think the odds no longer properly represent the likely outcome, even putting money on the
unlikely outcome from time to time, knowing that the payoff will exceed the risk. A smart gambler takes the long view, knowing that while most bets placed on unlikely outcomes won't pay off, those that do will not only cover the losses they will provide a profit, because they knew when the odds had gone too far and were no longer correctly predictive of the chances of the outcome happening. Of course these bets placed by smart gamblers taking the long view themselves contribute to the book readjusting their odds back in the other direction, so that
they can make money in the long run. If too many gamblers start placing money on one outcome - whether the bettors are smart, or are simply driven by loyalty to a team or superstition or whatever - the odds will start shifting in the other direction and then the good gamblers will stop placing their money on that. This is a kind of "market equilibrium", but it's
not about finding the likelihood of the various outcomes, it's about finding the discrepancy between the odds and the likelihood of the outcomes. At any given moment, an average gambler won't know whether the "market of the betting" has happened to find the correct predictive power on the outcome of the event being wagered upon. Knowing when the odds happen to be predicting the outcome and when they aren't is what makes a gambler good at gambling (it's not the only thing, but that's part of it).
EDIT: I tried betting on MMA for about a year, when I was deep in following the sport. I wasn't bad at predicting the outcomes - I was well above .500 - but I slowly lost my stake over the course of 14-15 months, because I wasn't good at playing the odds. If the odds were merely predictions of the outcome of the event, I'd have been making money. But from the book's perspective - the very person or firm that sets and then constantly adjusts the odds - that's exactly how it's supposed to work. I was the perfect mark.
