Windows 11 dev builds have an accessibility feature that allows you to use one webcam in multiple apps simultaneously. However, it is more likely to be used as a streaming tool.

Windows 11's latest dev build has a new feature that may be worth updating for if you are a streamer or have accessibility needs. You can also see your face on multiple apps if you want to. Give it a few more months before you see the feature in a stable version of Windows 11.

Windows Latest reported, citing @phantomofearth, that the original feature was intended to be a tool for accessibility. I personally verified this by spending hours while waiting for Windows updates. The feature is "designed for the hearing-impaired community", but it doesn't specify how to use it.

Sign up for the latest Windows 11 dev build: 10.0.26120.1542. Once you've got this, you need to go to the advanced camera settings to toggle the "Multi App Camera", which by default is off. You can only get this far by using a tool to turn on the features that have the correct feature ID. (Thanks XDA for your help).

This is to say that it would take hours of work to make a very minor change, and it might only be worthwhile for the accessibility purposes mentioned above.

Streamers will benefit from this for one main reason. You used to need two webcams, or separate rigs, to stream games with a Face Cam and talk on Discord at the same time. This new feature allows your friends to see your face on Discord and your audience will also see it during the stream. This is a very niche feature, but one that the right streamer might find useful. When enabled, you cannot access in-app features and must change the brightness through Windows settings. This limits its use.

You could argue that transcription or lip-reading software is more accessible. It can pick out words while also giving you a written record of what was said. This is just a guess on my part, and a quick Google search does not satisfy my curiosity.

If this is included in a future Windows Update, we will have a better understanding of its accessibility purpose. For now, it's been a few painful hours to verify it exists. We don't yet know when it will be included in a public Windows update.