Maybe the reason why VR hasn't quite caught on is because the existing devices in the market aren't really all that good, and Apple's offering just might be the first product that doesn't suck to use.
I personally admit that I don't see myself using it for productivity all that much, and maybe initially for passive content consumption that does not require much interaction / input on my end. Once it becomes more socially acceptable to be seen with this in public, I can see more people using them in places like cafes, libraries and public transport.
If it's acceptable to be watching Netflix on your iPad while sipping your coffee at Starbucks, what's wrong with then doing so using a mixed reality headset? I am not really bothering anyone else, and there's better privacy because other people can't see what's on my screen. Same with browsing the web in the library (it could be a nice alternative to carting an external display for my laptop), or attending a zoom webinar while I am in the way home in the train (it's hands-free, meaning I don't need to use one hand to hold my phone up to my face, allowing me to have both hands free to say, hold on to the handrails in the carriage).
Likewise, I am no longer confined to interacting with AR content through a tiny smartphone display that I have to keep holding up (think Pokemon Go). My entire field of view is my playground.
The ability to basically have a 4k display whenever you go, without having to actually hold it up, will open up a lot of use-cases, IMO.