Why? Because social gambling is probably the most difficult type of gambling to regulate. Social gambling seems to be the only way to physically bet in Hawaii without breaking any laws.
Gambling laws in Hawaii are pretty strict, so if you want to place a wager on anything, your options are few and far between. Most authoritative parties want to keep their tourism wholesome and streamlined. Tribes and officials alike have been trying to make a push to build casinos in Hawaii, with no luck. Their hotels don’t have any casino activity within them - not even a slot machine. Their whole economy revolves around tourism though, and being able to provide visitors with a sportsbook in proximity to their resort and hotel locations could prove to be a good revenue stream. Hawaii isn’t known to be a sports betting hotspot, they only have a few college teams, so the push for sports betting legalization in Hawaii just isn’t a priority to governing officials. This ban extends to other prominent providers in the States, such as Caesars, PointsBet, BetRivers, Fox Bet, and Unibet. *Hawaii is a state that has never shown a great deal of interest in sports betting, which is why major US oddsmakers like DraftKings, BetMGM, and FanDuel are now offering their servies there.