ios/macos already let you copy/paste between them if you have bluetooth enabled on both sides and are signed in the same icloud account on both. I wonder if they're planning to let me authenticate/webauthn on macos using my phone as a platform authenticator?
Possibly - there is functionality to expose an authenticator over bluetooth or NFC, both of which would work for an iPhone or watch to act for an authenticator even into a windows laptop.
There are UX issues there that have to be solved yet. Also, while I haven't gotten my hands deep in what Apple has done yet I suspect this is a browser-level feature and not a platform-level feature, where say your phone would pop up a "do you want to authenticate" screen when held near another computer with BLE the same way you get "do you want to use Apple Pay" today.
Platform level support would allow me to use this directly within other applications and browsers, rather than just from Safari and the SFSafariViewController/ASWebAuthenticationSession Safari-managed views.
