It's literally a 70" HD display around 4m from your face. All HD displays fit exactly the same amount of text in their 1920x1080 pixels, the only thing that changes is the field of vision the display takes up.

I use them to do work, the issue I have is, having owned three pairs (for reasons), the lenses can be hit-or-miss. The pair I own now is more on the miss side, and some part of the lens is blurry. You don't notice it when watching films, but it's noticeable for text. The other two pairs were OK, this one I got less lucky with.

This one also seems to tire out my eyes if I wear the glasses for more than an hour, and I don't know why (it might be the blurriness). It's not the focal distance, they did a good job there, it's about 5m as far as I can tell.

Anyway, overall I like the glasses. They're worth the 200 € I paid used, but I probably wouldn't pay 400 € for them, I only use them on flights. They'd be great if I watched lots of movies or played games on a Steam Deck, though.