Agreed. Web apps have no business knowing what my audio config is. Instead of the OS or browser implementing a working sound picker, every single website will have to do it and all but the big ones will do it slightly wrong. Google is positioning the web for them to take over the desktop.
It's more easily explained as always wanting your web conference call to use your headset even if normally you want the browser to use something else than as a replacement for changing your OS settings.
The web is constantly positioned to takeover the desktop though, has been for many years at this point.