You are being helped by an excellent salesperson who has been working there for twenty-five years.
Even an exceptional salesperson has an imperfect memory.
The salesperson recognized her and reappeared with a small box.
So the salesperson says, "If you like that suit, then come over here and try this one from Ralph Lauren."
In general, when you have such a salesperson, the information is useful.
Returning to our twenty-five-year-veteran salesperson, let's say he has been replaced by a robot powered by a version of Amazon's suggestion engine.
When the salesperson rings up your purchase, no one tells him he had better forget what shoes he sold you with that suit and not to use that information to advise any future clients.