Anyway, I'm guessing the answer to your question is: control. You know that you can at any moment tilt your head forward and lose the vertigo sensation. So you are safe and in control and you also feel safe and in control. That makes the experience enjoyable (I assume).
Ah. See, I have this vertigo too, but it's always on. And I stumbled on escalators a couple of time already, so that increasing my vertigo with 30-50 meters below me doesn't feel like a particularly good idea.
Probably the same way that some people enjoy roller coasters, sky diving, walking tightropes, climbing vertical walls, ski jumping, flying trapeze, skating or boarding down a "half pipe" and various other "extreme sports" without getting a panic attack.
Anyway, I'm guessing the answer to your question is: control. You know that you can at any moment tilt your head forward and lose the vertigo sensation. So you are safe and in control and you also feel safe and in control. That makes the experience enjoyable (I assume).