AR/VR doesn't work the same way as a 2D screen because of the lenses. Your eyes are essentially focusing at infinity.

It can lead to completely different problems, mostly in children. Adults instead get terrible motion sickness if you're not very careful.

No idea about the eyesight, but a personal anecdote about the eyetracking for the cursor/selection: It's an existing assistive technology and a few years ago I tried it for fun for a day. It can get tiring and you really exercise the muscles moving your eyeballs. I suspect it's something that you train / get used to in the end, but it's definitely an unexpected strain on the body. I suspect that's going to become a new thing people experience like the texting thumb RSI.

Focal distance with most of the VR headsets are around 1.5 meters. (Thanks to the optics)

There is no scientific consensus, especially long term. But with all things, if it's not what nature designed us for, it's probably not great, if not terrible for us.

Then add the developmental result of having a child with this strapped for most of his puberty (you know it's gonna happen), and I am glad I'm too old to get sucked into this fad.

I feel alienated by how positive the reception for this thing is.

Since everyone responding seems to be missing the point: are there electromagnets in this, or anything else that could impact brainwaves, cell behavior etc?

You won't be able to wear this for hours every day since the battery won't last more than 2 hours.

Luckily, we're being constrained by battery tech.