It would be amazing and seems like a straight forward extension of the charge card industry. Of course end user machines will have to be updated, but that can happen over a period of years, but it is a straight forward extension.
And the email / identity shouldn't be disclosed to the sellers, instead the receipts should be sent to charge card's infrastructure along with the charge/payment. And then from there it is distributed to the users.
Maybe Apple and Google and Samsung could somehow extend their Apple Pay / Google Pay / Samsung Pay APIs to enable receipts automatically and start to push for that. If Apple advertised it in their keynote, and say StarBucks and Home Depot and Walmart supported it, we would soon have this everywhere.