Fair point, I’m not super familiar with hello. The problem of cross-computer access is solvable* - add cryptographic trusts to transport encrypted data across insecure hardware.
*I didn’t say it’d be great user experience though.
*I didn’t say it’d be great user experience though.
In principle it's similar to the password manager problem, which is a bit ironic: if everyone used password managers, most of the same security issues would be resolved. (There are a few cases where a FIDO key is better than a password manager, but not many!)