... I am either the stupidest human on the planet or you are wrong in every way I can possibly imagine. ...
Neither. The argument's fine, and, while thinking isn't necessarily your strong suit, there are dumber people around.
Which is not to say that your post is without merit. For instance, your point about the cost of your "device" is perfectly valid. If my bank charged me for my debit/credit cards, and charged me a fee to use cash, I would be forced to add that to my cost of transacting in fiat.
So point taken, make it "MORE THAN $6 per transaction"