U2F is an open authentication standard used worldwide. It enables relying parties exposed to the internet to offer a strong second factor option for end user authentication.
Materialize by a device implementing the U2F protocol, this second factor brings many advantages to both sides. Allowing to reduce over-reliance on passwords, it increases authentication security and simplifies passwords.
U2F is increasingly supported and adopted worldwide, it is present on all the most used browsers, and is also arrived recently on openssh 8.2:
https://www.openssh.com/txt/release-8.2, still showing that its adoption is exponential.
Qemu, which is an open source project for machine emulation and virtualization, should integrate U2F support, especially for all users who wish to take the advantages given by U2F in guest machines.
There is no doubt about the benefits provided by U2F and its widespread adoption. Integrate the support for U2F in Qemu is a good idea.