The subject basically pretends that everything that hypnotist says is true. Have you ever played a video game and got so wrapped up in the virtual world you just stopped noticing the real world? That's called immersion, and it's achieved by keeping your attention focused on the game. When your attention drifts away from the game, you start noticing that it's 2 am or that's you've been playing for four hours, and you remember that you are not in the video game, you're just playing a video game. But as long as your attention remains on game, your feel like you are actually living in the video game's world. Gamers love the feeling of immersion, so developers put a lot of work into figuring out how to keep gamers attention, which maintains the immersion.

Hypnosis works on the same principle. The hypnotist uses the patients full attention to create an imaginary world that feels real to the patient. The difference between video games and hypnosis is hypnosis patients actively give their attention to the hypnotist, while gamers passively expect the game to take their attention. When a hypnotic induction starts, the subject is asked to imagine the something in great detail, effecitvely putting the onus on the subject to make sure their attention is doesn't drift. But when a video game starts, the gamer just watches the screen and expects the game to be interesting enough to keep her attention.

Hypnotism is more immersive than video games because the subject is helping the hypnotist keep her attention. This allows the hypnotist to create a virtual reality that is more convincing than video games. But it's still just a game of pretend.