Actually good point, looking at that article again, 190° is edge-to-edge — i.e. also including single-eye areas.

True binocular FOV is 120° horizontal, which makes it close to a square actually.

It’s not like that remaining 70° is completely useless for monitor viewing, you will still peripherally notice any major display changes in that area, and should you need to turn your head, the partial view makes it easier to quickly find and lock onto the new target.