It's not even a Mac - it's really an iPad with a creative user interface (hardware power overlaps significantly between iPad Pros and low-end Macs). VisionOS, however, is much closer to iPadOS than to MacOS. It IS a super-creative user interface, and I have no doubt that it will be the best consumer XR headset yet. It uses significantly higher-end hardware than any other consumer-grade headset (is anything else even 4K)? Apple is also clearly the best UI developer in the industry, so I have every reason to expect that the UI will be less clunky than any other headset, probably MUCH less clunky. Apple stuff Just Works, and it has Just Worked for me since my 128K Mac (I'm going to buy a really top-end 16" M3 Max MacBook Pro right around my first Mac's 40th birthday, and there have been a LOT of Macs in between). My question about the Vision Pro isn't whether it will Just Work (I'm reasonably certain it will), but what it will Just Work for, and whether that slot is worth $3499+?
The problem is "what's the killer app for that UI"? To sell in large numbers, it needs something that only it can do, and that justifies a price that otherwise buys an M3 Max MacBook Pro. Maybe I'm misjudging how much room people have in their device-buying budgets, but I'm guessing that most people (who have room in their budget for even one $3500 device) don't have room for two - and that one slot is generally taken up by your Mac. I could buy a Vision Pro if I REALLY wanted one, but it would mean living with my 2019 Intel MacBook Pro for another couple of years, instead of upgrading to the fire-breathing M3 Max I have my eye on. Since VisionOS is a variation on iPadOS, that means that you're accepting something with iPad style software limits as your "big device", and accepting that XR is going to be your primary computing interface.
It's also super-expensive if it's taking up the "TV" slot in your life. Maybe it's a fantastic device for watching movies, but is it a BETTER device for watching movies than a really top-end TV in the 80" range? You can have 8K or OLED around 80" in that price range (but not both). Or is it better than a nice 65" OLED and $2000 worth of home theater gear? Those are its competitors as a home entertainment device, and they're formidable.
The third possible app is as an ultimate videophone. I have no doubt whatsoever that a Vision Pro will be the best POSSIBLE device for FaceTime (and for Zoom, Teams, etc. when the apps become native). The question is whether there are enough people who do enough videoconferencing to buy a $3499 personal videoconferencing device. Expensive videoconferencing tools traditionally bring in a whole conference room, not one person working at home. For the maximum benefit, everybody has to be on a Vision Pro. Is there any scenario outside of Apple itself where that's likely? Maybe military officers and executives who travel a lot connecting with their families? Enlisted personnel and other travelers might like it, but you'd have to be pretty senior to afford it. And, assuming there are kids or pets, it would be hard to have another Vision Pro on the family side (try getting a headset on a Golden Retriever)...
It would be a great tool for online classes, but even Harvard can't afford it for everyone (they didn't even hand out decent webcams during the pandemic - I was a grad student there and had quite a few classes where Chromebooks and cheap PCs with ridiculously terrible webcams disrupted Zoom classes). If a place with that kind of resources won't loan out $100 hardware to make online classes work better, good luck getting schools with LESS resources to hand out $3500 devices. If you're wearing a Vision Pro and someone ELSE pops in with a Chromebook, you still get the disruptive video glitching and audio dropouts. To make online classes work better, everyone would have to have uniformly good hardware and connections. You would also have to use something other than Zoom (which glitchily conserves bandwidth no matter how fast a connection it has). A whole class on FaceTime with Vision Pros WOULD be better, but that would be very hard to arrange...