Re: shared device use, yes, you would continue to do password management best practices (fingerprint scans, master passwords, etc.). I see the transferability

Re: shared device use, yes, you would continue to do password management best practices (fingerprint scans, master passwords, etc.). I see the transferability as an export/import format issue. W3C, browser vendors and password managers need to agree on a format for keychain export/import. Note that this technique could still be used in conjunction with multi-factor auth. Since it is just an evolution of passwords, those type of mechanisms are still relevant and compatible (though, eliminating knowledge factors should reduce need for a second factor).