I've wastefully spent money (not $3500 though) on new tech that I liked the idea of and wanted to see more of in the future, but provided little guaranteed immediate benefit. e.g., Oculus DK1. Or a wristband that let you control your laptop with gestures. Or a table tennis robot. Or a pod that monitored audio queues in the house. And who knows what else. I imagine for this individual, it's not dissimilar, just scaled up a bit.
If Vision Pro can deliver something that allows someone to watch movies and browse hands free and maybe have a courtside NBA experience, even if it never becomes a work-all-day solution, that's worth something to many people.
i think a lot of people will pick up a Vision Pro just to see the hype