Earlier quoted context omitted.
One reason is to load it into their employers expense system for reimbursement... My company credit card expenses automatically show up in our expense system for easier expense reporting. Another reason is so I can audit the charges -- if my credit card had an option for "Don't track individual purchases", I wouldn't use it since I want to look at the charges at the end of the month and make sure they were mine.
Going even farther, I'd love it if full receipts passed through the credit card system. Yes, my credit card company would mine the data, but replacing "$20 at FOOCORP on 11/23" with "$20 at FOOCORP on 11/23 " would be well worth it to me. (I wrote up something advocating this in https://www.jefftk.com/p/attach-receipts-to-credit-card-tran... )
This is especially true for air travel, where ticket details are almost always attached to the charge. However, I’ve started seeing it done at some large online merchants as well (e.g. Amazon). It’s typically used for expense tracking on corporate p-cards.
It’s rare to see the additional details displayed for consumer accounts, but the data is there on the backend.