[tln]

Perhaps he is factoring is the human cost. Yubikeys save a couple of minutes multiple times per day.

[pc86]

I took it as the cost of just purchasing Yubikeys for everyone was less than the payroll and associated costs of developing the Authenticator app.

But I could either interpretation (or both) being correct.

[organsnyder]

Could also be the security benefit. Authenticator-style apps are still vulnerable to MITM attacks, where physical keys are not.