[hakfoo]

I suspect it's another step in the push to make the mobile device the centre of digital identity. (Yeah, it might support some standalone key devices, but nobody's giving Joe Sixpack a Yubikey)

The one with far more data gathering capability and generally less robust ability for the end user to assert control over it, and which is generally tied to a service contract that in many countries requires identity verification.

[tacticus]

That would require all the microsoft auth platforms to allow you to use yubikeys or similar instead of default forcing you in to ms authenticator only

[jdmoreira]

Microsoft authenticator supports YubiKeys