To be fair, most people already do this anyways by using passwords multiple times. At least they have no illusion of security. The scheme you showed provides l

To be fair, most people already do this anyways by using passwords multiple times. At least they have no illusion of security. The scheme you showed provides lots of illusion, and zero security. This matters because, for the same effort, users can get much stronger security, even a cryptographic guarantee of password independence. (Leaked site passwords yield zero information about other site passwords, even if they're derived from the same root). But they will not seek out these solutions if they are mislead into using broken schemes instead. There are also two memory banks in a yubikey so you can set two different keys and alternate them using the schema I put forth above. That's still terrible.