I'm not aware of official Vegas betting on disc golf. Other posters have suggested reasons for this, which basically come down to scale and 'legitimacy'. As for the 'vig' which is short for vigorish, it is merely the oddsmaker's cut of the bet or 'administration fee' and doesn't not affect odds, merely one's calculation of the bet's worth to the bettor.
In the past there have been several 'unofficial' bookies taking bets for larger events, notably Worlds in the early 90's. As I recall, the only options were bets on individuals with their payoff odds. My memory is a bit foggy on this point, but one year Climo was favored @ 1 to 3 (you win 30 cents for each dollar you bet, if Climo won). As it was 'informal', this particular bookie didn't take a vig...
Despite the fact that the gambling industry is filled with corruption (and other sorts of more pernicious crime), I am always puzzled by the US's strange 'mixed' stance towards it, as if governmental oversight (lottery) and limiting it to small areas (Nevada, NJ) legitimizes the practice. Caveat emptor.