Joking aside, I don't see the point of this. It guards against exactly one attack (your password manager somehow revealing all your passwords) which is unlikely, but not against a whole lot of other (slightly more generic malware, phishing, ...) whilst making logging in harder (there's now a manual process).

If you're willing to go such lengths, enable 2FA on more accounts (which the articles mentions, points for that) or get a physical token for your password manager.