Endless. From medicine to better mil/leo training, Molecular engineering/genetics... If you can get an accurate model and behavior set it’s massive what you can accomplish.
Right now I have more rendering/visualization power in my gaming rig than every computer in Hollywood had combined when they made Babalyon 5. And by a wide margin. And my rig is small compared to many.
Back in my previous life (1998/99) I was using VR for maxillofacial surgical planning. It’s a very powerful tool.
However, you can really mess with grad students. You get them in the sim room, stick the headset on, then switch left and right eyes. It’s amazing how quickly the brain adapts to seeing depth in that situation.
At the end of the clinical study, they’d take the glasses off and fall over. Endless fun.