I might not get everything right, but aren't they proposing "kind of" a keylogger as a security solution? Even the idea of using a technology for which others build products to fight against seems a bit strange.
Now, admitting that everyone will use it in good faith, I'd like the fact that, by itself, it does not add another thing you need to do as a user to authenticate. But, as Paul said in his article, I only see it used as a trigger for other security measures.