I had a very good look at the 'cam at an Apple store just yesterday.
First thing I want to highlight (for what it's worth) is that the device itself is just gorgeous. Fantastic build quality as expected; the panel quality is better than the 5K iMac with greater contrast, and the backlighting consistency/viewing angles were excellent. The speakers were the most surprising feature to me, I felt they sounded better than my HomePod mini. This might have a lot to do with the greater stereo separation, but regardless I was almost shocked at how good they were.
The webcam. Honestly, it's about what I expected - the equivalent of taking a FaceTime call from an iPhone or iPad through a large display. Even with the good lighting of the store, it had the telltale signs of a small sensor with high levels of noise and grain.
This is not a bug or something that can be fixed through software - it is the nature of a small camera. So in this regard, I don't think anyone should be surprised at the image quality. The real topic isn't how it looks to you the host, but how others will receive it.
Therefore, I don't think the nature of the camera is any better or worse than if you were conferencing from another Apple device. The issue with the Studio Display is that because the panel is so large, the image quality is amplified many times over. So what looks good on a smaller device, suddenly looks like a potato cam. But what I would be saying to myself is, "will the person on the receiving end be viewing me through a 27" display, or something more common in the range of 21-24" for a desktop, or a notebook?". In these instances, the image quality would be on par with what we've come to expect from other Apple devices and the issue isn't present.
Just my thoughts. It doesn't excuse the wildly inflated RRP, but product really is excellent and if I were looking to buy one, I would put aside $100 for a Logitech Brio/Streamcam.