Here's a video I shared a few years ago, but has become even more relevant under today's pandemic circumstances. More and more people are working remote and having to deal with live video conferencing / meetings. Instead of a poor quality webcam, with this adapter you can capture the HDMI video feed (up to 4K resolution) and turn any professional camera into a webcam for conferencing applications like Zoom, Skype, Hangout, and even Facetime. Or use it for live streaming through services like Facebook or YouTube Live.
Yes there are cheaper video capture adapters, but most are only up to HD resolution. Even though most streaming services only support HD, by having the option with 4K resolution, you can use the extra resolution for faux camera angles and simulate a multicamera production. If you're offering a live stream service for a business or company, this could greatly help turn those boring static camera angles into a more interesting and engaging presentation for the viewers.
Software like OBS will allow you to create 'scenes' in which you could zoom in to different parts of that 4K resolution and then toggle between them by just using your keyboard. Live Keying (such as green screen) will also benefit from 4K capture as you have more information to work with. So virtual backgrounds will be cleaner. Not to mention that 4K just looks better when downscaling. So yes, while there are cheaper solutions to turn any camera into a webcam, not many can capture 4K resolution like these Epiphan Video Capture Adapters.