Xander I can't remember that I came across a store that put the product I bought from them in the description of the payment. Do you ever experience that? I am curious which one that is. With services that happens sometimes, but not always. Anyway, if you get a bill from KPN for the month of May then it is of course not expected that it is for your car insurance. By the way, insurance companies do it regularly because otherwise you no longer know which payment is for which type of insurance.
Incidentally, I occasionally put in the bunq app what I have bought, to be able to search back, for example. Or to know in 2 years time why I had already spent so much money at that store.
Patterns are of course always much nicer than incidental promotions. Supermarkets can of course see what you buy from them and send personal offers for their own brand peanut butter if they 'discover' that you buy a jar of peanut butter from an A-brand every month.