I also tried a similar setup (with gphoto2 getting the stream of jpegs, ffmpeg, loopback device) but the deal breakers for me we're:

- high latency: in the half-second range, consistently out of sync with the audio - bulkiness: I had to place the camera on the side of the screen rather than on top, so I consistently looked away from the camera

With that experience I didn't find it worth to upgrade the setup (with mini HDMI cable, capture card, power supply) and ended up buying a crappy webcam instead