In a FAQ for Windows 10 S, Microsoft admits “you are able to
download another browser that might be available from the Windows
Store, but Microsoft Edge will remain the default if, for example,
you open an .htm file.” This means if you click a link from
another app, or open a link from an email then you’ll be thrown
into Microsoft Edge, even if you wanted to use another browser.
It’s not clear if Google will even bring Chrome to the Windows
Store, but if it does then it might be a pointless venture as it
won’t be fully functional without being the default browser on
Windows 10 S.
Likewise, Microsoft is also crippling its own Edge browser. The
default search provider in Microsoft Edge and Internet Explorer in
Windows 10 S cannot be changed. Bing will be the default, and
Microsoft is preventing users from switching to Google or other
search providers for some unknown reason.
It’s not an “unknown reason”. It’s an obvious reason: they want more people to use Bing, and if they can only use Bing from Edge’s search feature, more people will use Bing.