The feature is called “Continuity Camera”.
I have a friend who lives in a high rise with incredibly crowded wifi spectrum. Anything wireless that involves latency sucks in their apartment. They tried to use an old iPhone for VC, but the jitter added by their crappy wifi made that a non-starter. By contrast, this product uses a USB connection, and I'm guessing would perform far better for them (and really anybody with crappy wifi, which is most people).
Maybe try Googling again?
https://www.theverge.com/2022/6/6/23156834/apple-iphone-webc...
As for the issue with wifi, that's a legitimate shame for your friend, but isn't a reason for the feature not to exist for anyone.
I agree that it would be awesome to use an iPhone in this context. But given the problems my friend has, and given the problems in general with mac wifi and latency, any use as a webcam would be far better if it were wired. Hopefully that will leave a niche for this company. That, and using Android phones, and hooking any phone to a Windows box.