Although I think overall it'll add more interest, I likewise think there might be some growing pains that come along with it.
Gambling sites are gonna be quite pervasive with ads /commercials that are going to be much more common, borderline being an ongoing nuisance. To the point where some might actually miss the Cialis commercials, if that's even possible. It won't be just for pro golf, but every sport.
The in-game gambling or "situational" gambling is probably what concerns me most, as it relates to golf. Some are gonna show up to spectate in the final round, having a monetary interest in the outcome based on the wager they placed the night before, or prior to the final round. The tour will have to navigate these waters much more closely than they have in years past. The last thing anyone wants is a tainted outcome from someone who thought it financially beneficial to yell or scream while a player is hitting, or being a negative disruption, that might impact the end result and impact the overall integrity of the competition.
With this new precedent of legalized gambling, if/when it goes into effect, it will (or should) effectively put the tour on notice that they have to nip the gallery disruptions in the bud, a no-tolerance policy.
People will cite that sports gambling hasn't been an issue in Europe, and for the most part it hasn't been. But we're also talking about a different culture that deeply respects the decorum aspect of the sport. We've yet to get to that level of respect and decorum here, as it's become more and more an issue here in the states in recent years.
The tour will have to enforce a zero tolerance policy, and they've been very hesitant to do that in the past. This will force them to change that.
I don't think it'll be an overwhelming impact, but like I said - there's the possibility that it will come with some growing pains.