You’d be surprised. The immersion can be quite realistic because of our willingness to cooperate, just as in the movies.
I would predict, if such a thing ever did “take off”, the information would be carried on optical tranmission lines. I’d guess one could put a thousand “visits” on one line.
That would make it very competitive with air travel.
First class, of course, would mean you’d have the ability to read through your avatar’s eyes; (Necessary for a business meeting.)
That part, I don't think so, or only in part. Reading is obviously necessary for business meetings, but in my experience reading and observing others (their current focus of attention, their expressions, body language, etc) is also important.
In my meetings, "reading" is usually performed on a document in the laptop in front of me (and finally I have a corporate laptop that doesn't "hide" other participants behind its over-tall screen). Once in a long while it's something projected on a screen (which I dislike).
When it comes to discussion I strongly prefer to see my counterparts' faces because there's a LOT of feedback there even when they're silent. In my last face-to-face meeting, one participant was extremely concerned about a particular issue before us; voice communications would have conveyed some of his concern, but body language conveyed even more.