Mike Schmitz has a great review of the Opal C1 on The Sweet Setup:

Hands down, the Opal C1 is by far the most impressive webcam video I’ve ever seen. I’ve tried just about every premium webcam out there, and in my opinion the Opal C1 is truly head and shoulders above everything else.

Mike also touches on why you may still want a webcam even though macOS Ventura will make it super simple to use your iPhone as a webcam:

I don’t want my iPhone on top of my computer all the time

That's really it for me too. The Opal C1 looks nice and is pretty small, while an iPhone is large and honestly doesn't look great just hanging out above your computer monitor all day. It may work for some, but not for me.