• If you didn't recognize a charge, seeing what it was for could remind you.

• If you needed a receipt for taxes or reimbursement one could be captured automatically.

• Personal finance tools (or corporate equivalents for company cards) could track spending with higher granularity.

• Because the credit card company knows what the items are they can better detect fraud.

Receipt data isn't currently part of the protocol used for charges; you'd need to spec out something that let companies communicate everything a receipt can communicate today. This would be a very large change, but everyone who would need to make changes can have incentives in the right direction:

• The card company likes it because it can market their card as supporting receipts and better detect fraud.

• The merchant likes it because they see fewer chargebacks and the credit card company probably gives them slightly better rates.

• Point-of-sale makers like it because they get to sell a lot of upgrades.

The main downside I can think of, aside from it being a lot of work, is that people might not want their credit card company knowing the particular products they bought. The company would probably want to sell this to marketers, though there would be plenty of time to pass regulations limiting that if we wanted to. Personally, I don't mind: the merchant is probably already selling my purchase information or will soon. And the money the credit card company gets from selling the data, since it's a competitive market, probably mostly gets passed on as higher cardholder incentives or higher incentives to merchants to adopt receipt sharing.