There is a fundamental difference between a medium of exchange whereby the government would have to devalue or interrupt everyone who holds the instrument in question (like by invalidating a series of bank notes) and one whereby someone can decide that you personally are no longer allowed to use the medium of exchange. Those things are not at all similar.

This long rant strikes me as having been written by someone who doesn't know anyone who has been summarily excluded from the banking system. If you're not viscerally aware of the power that one random faceless person at Chexsystems would have over your existence in a cashless world, you're missing the point.