Flying Adler approach works and is the solution for noobs. Pros either use a real world keyboard or just look at the letter they want to type and snap 🫰 like this to type that letter. You can type pretty fast with the look’n’snap technic.

From the article:

Your eyes are your mouse when using the Vision Pro. When typing, you look at a virtual keyboard that hovers around, and can be moved and resized. When you’re looking at the right letter, tapping two fingers together works as a click.

So they were working backwards to determine the inputs based off of the observed eye motion.

I have a much less modern VR headset and you can definitely still type on a regular keyboard while you're wearing it. You can't see the keyboard though, so you need to be skilled enough to touch type. I can't find any reliable-looking statistics on it with a quick search, but it seems like that is not a very common skill