It is worth knowing that they are all online casinos. No need to differentiate them.
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.
Even can casinos are VR headset to provide 3D gambling experience for their users already. No matter how it get complex like the Meta verse, as more people are embracing it and using it, gambling sites will also get involved. You are right about that. They are not a threat.