I would not call them a threat at the moment. The technology is still very crude and is far from mainstream adoption. It also is not a threat when it can be adopted into the current casino system, as it gets more popular more casinos will integrate it into their system and it will start to get more refined when more investment funds are pumped in as each tries to outdo the other.
- Jay -
Casino owners are business people and if VR becomes a thing that majority of gamblers are interested in the future I'm sure that they'll integrate it into their games. Having this assumption in mind I don't think that VR or AR will be a threat to the existing physical and online casinos, online casinos haven't stopped people from gambling in physical casinos so I doubt that VR will be a threat to gambling in general. Change is constant in life and VR is welcome to join in giving gamblers more experience, that is if majority of gamblers embrace it
What is definition of threat? If VR or AR is a threat, then it will make the current way of online casinos go into existence not the casino itself. The casino will adopt the new method to implement VR and AR games in their online platform of physical casino.
Virtual reality cannot be a threat to gambling, which i know OP never stated it to be like that. It will only bring about a change in the gambling surrounding where the activates will take place. That is there will be change in the way users interact with the casino.