Ok. I thought the receipts will be made readable for anyone to see on the internet. If they are only readable for the user and the merchant then good. Theres no need to do anything else. All Im saying is the potential use case for decentralized receipts will go hand in hand in a reputation system of Open Bazaar or some platform like it.
I think you're confusing our receipts and invoices. An invoice is where a customer generates a request for payment, like a bill, with a bitcoin address and things that need to be paid for. These invoices are encrypted.
A transaction receipt is just like a confirmation that a transaction was successful, and that x BTC was transferred from address y to address z.
Dont they come together? After a successful purchase the buyer should hold a receipt from the seller as proof that the said purchase took place with all the details of the transaction in it. Again, this will be put to good use in a decentralized reputation system. The more successful transactions as shown with the receipts the seller issued the more points he gets as a trustworthy merchant.