The xReal ones are extremely workable. Like, you wouldn't want to do it by preference if a good monitor was available, but easily good enough for a situation where you don't want to use a monitor or don't have one.

I also have the Viture Pros. They are awesome for airplane/hotel use. Not great as second monitors, as you say optically they aren't perfect and text makes that show a bit more... but if you hook up a steamdeck or want to watch Netflix on the go it's great!

Don't get me wrong, they work as a monitor in a pinch on a plane when you need privacy it's just not going to ever replace a real monitor for you.