Earlier quoted context omitted.
Not sure why that would be any different than credit card payments, which don't itemize every purchase either - they still know how much and to what seller, tracking a seller and banning them seems just as easy. What they don't get is the buyer's information. ...except for the time and place, with a device that almost certainly has cameras for theft deterrence. Which might be fine now, but seems pretty law-enforcemen…
CC's do get transaction information. Check out "Level 3 data" https://www.tidalcommerce.com/learn/what-is-level-3-data
Many shopping carts don't bother sending the data, because they'd rather say "let's support 900 obscure payment platforms in a de-minimis way" than "let's support a handful WELL"
Then there's actually getting the right information into the message to the processor. There's vague and inconsistent documentation on how to tag things like "commodity codes" and data formatting (Should the per-unit price be rendered as $12.79 or $12.7903?)
Even if you have the right intentions, you can easily blow things up by just having out-of-bounds data-- encoding a nonsense discount or tax rate.
What happens is that people set up software that sets up bare-minimum and mediocre data for every order that's good enough to get the "you sent level 3 data" rates, and the actual visibility is still quite poor.
Maybe there are some top-tier merchants who actually do everything right, but there's a hell of a lot of noise amid the signal.