That's enough information to correlate spending by specific guest. Also, if you've ever used that same credit card to purchase something on shopdisney.com or book a hotel room with them, then they have even more information on you (address, e-mail, phone, etc).
Edit: Just to clarify, I agree that what they're looking at is averages and that's kind of my point. Actual linking of a transaction to a specific name is a challenging and expensive task that won't be entirely accurate. Some suggest that they know everything and what I'm saying is "not everything".
I still think, even if it's allowed (credit card tracking), that it's a lot of work. More than it's worth. Paying someone $20 an hour to track thousands of transactions in an effort to maybe squeeze $5 out of people? These are low dollar amounts and not worth it, IMO. It'll cost more to pay employees to track this information that they'll make back, again my opinion. I'm sure some of it is automated, but even then, with people having multiple cards and family members, it would be hard to make it all guest specific and be accurate. They can paint a picture, but it won't be 100% accurate, nor is it worth it, IMO.
Disney invested all that money into RFID
Many believe this to be a poor decision, FWIW.
The system routinely has issues and to the point where the bands sometimes don't even work at the main entrances. While in general, they do their job, there are still accuracy issues with the data.
Especially for those who pay in cash, it would be hard to tell who, given how crowded some areas can be, is paying. That's if the band is working too, like I said, mine's about three years old, so it wouldn't do what they want it to. Also, day guests and offsite guests may not have a Magic Band at all.
I think it's far better to use the MDE app data, but even that can have reliability issues. There will always be margin of error.
I think it's closing
My mention is a placeholder for any quick service. It's closing, but being replaced by more quick service. So, the point still stands. Swap, Electric Umbrella for Pecos Bills, Sunshine Seasons, ABC Commissary, Pizzafari. Disney makes plenty of money off of these, but the real winners for them are the premium table service. That's what I'm saying. For Disney, it's easier to focus on those people because it's much more trackable since they all, for the most part, require reservations. It's easy data and the big spenders provide it. Same with things like the Bibbidi Bobbidi Boutique, easily trackable.
Quick service, that's not mobile orders, requires more work to track, and I'd guess even more work to track festival booths. The further you dig into guest spending, the more it costs. That's what I'm saying. It costs more and the gain is less and less.
[EDIT] It's a lot of work to prove a point of people a spend more than people b. You can come to that conclusion without it.