> FIDO2 can be used as a replacement for a username/password, so you can go to a site, insert your FIDO2 key and log in without any other information. Technica

> FIDO2 can be used as a replacement for a username/password, so you can go to a site, insert your FIDO2 key and log in without any other information. Technically U2F can be used to design passwordless scheme too (returning a big array of all key handles known to a service) but FIDO2 probably has some optimizations in this area.