I see two possible scenarios why Windows Hello seems to require Edge:

1. It is indeed dependent on MS Edge WebView, which is a dumb dependency to have for a security feature, especially as historical precedent (the 1990s antitrust lawsuit) and recent EU rulings suggest that Edge should be optional
2. System “tampering” (user taking back their rights) was detected, which disabled the feature.

I hope number 2 is the case. It suggests mistreatment of users, sure, but that could perhaps be patched out by a Powershell script.
On the other hand, if Windows Hello really needs a proprietary HTML renderer, this is a potential weak point and shows disregard of security in attempts to intertwine Microsoft products.