pro leagues like the NBA embracing the idea I see the next big thing in sports betting as credit cards issued by casinos.
The big advantage local bookies have over legalized gambling is the ability to allow bettors to place their action on credit. You place a bet with a casino - you put the money up front and if you win then you get your bet back plus your winnings. With a local bookie you just say "give me $100 on the Red Sox."
If a casino like the MGM issues a credit card that can be used for all the normal things a credit card is used for PLUS betting then that's a big win. Say you get a Visa credit card from the MGM casino with a $2,000 line of credit - you could used that card (if betting is legal in your state) to place that same $100 bet on the Red Sox but instead of fronting the money $100 of your $2,000 credit would just be on hold. If you win then that hold is removed and $100 is added to your account. BOOM!
If you don't pay your local bookie - he has to chase you down. If you don't pay your MGM Visa card - then the interest just keeps accruing. A legal debt. The vigorish on credit card interest is actually probably more than the vig on the actual bets. Plus the card vendor makes 1-2% on any purchases made with that credit card too!
Card issuers can also have rewards programs geared specifically to gamblers. Points could be earned both for normal purchases and for bets made. Frequent flyer points but for bettors. Maybe throw in a "free" 5-team $5 parlay once in a while or something creative like that. Maybe partner with other companies and have special offers. For example maybe a partnership with StubHub for tickets to your favorite team redeemed through points earned on the card.
Sports betting credit cards are the next big thing in legalized gambling. Write it down.