tomshardware[.]com/phones/android/how-to-setup-an-android-smartphone-as-a-webcam-camo-studio-unlocks-new-uses-for-old-smartphones-in-windows-10-or-11-and-obs-software
camo[.]com/studio
Les Pounder -- Tom's Hardware -- walks you through using the freemium Camo app to connect an Android device to your PC/laptop via WiFi and use it as a webcam, or 2nd webcam. While Les talks about needing a webcam in a hurry, I could see this being useful if/when you need a webcam just one time, or so rarely that it would be a waste to buy one. It might also be useful I imagine to have a wireless camera.