The controllers used for this video are probably the index 'knuckles' controllers that have some finger tracking ability. Therefore good replicas of your hand can be generated given the data passed about the location and rotation of the controller and the general position of each finger. Arms are quite a bit harder as the shoulder joint and wrist joint are both muliaxis (while the elbow is fairly fixed). While the location of the shoulder can be inferred based on the location of the visor and the relative location of the controller the full IK chain can solve a number of ways (With your hands on the keyboard notice that you can change the position of your elbow without much effecting your hand or shoulder position.) because of this an improper solve can throw off immersion, better and easier just to have 'phantom hands'.
Different games will do things differently. Some will display hands, others will display the controllers. You can do either.
After some time, you forget you are even holding controllers (on the Rift, I'm not sure about those clunky Vive controllers, and I haven't tried the Index).
> I'm not sure about those clunky Vive controllers
Vive owner here.
Depends on the game. In a game like PokerStars VR, yeah I often feel like I'm holding a controller. But that's not a game that aims to immerse you, as it's more of a social game. The real draw to that game is interaction with other players. VRChat is also in the same boat.
In any sort of shooter, not at all. Definitely still immersive and I don't feel like I'm holding a controller. This also applies to games where I'm holding things a lot, like Gorn. I feel like I'm holding inflatable toy weapons, which is fine because the weapons in the game flop around a bit like they're inflated.
Probably a mix of immersion and practical reasons. It looks like Valve is supporting a huge variety of input devices. Some, like the Index controller do track individual fingers. In a grittier game like this it would be weird to see the Vive magic wand floating around in space. With the gloves, they can also incorporate things like a health bar that would normally go on the HUD.
