It’s mitigation, not a perfect prevention, but those are extremely useful for security: if the attacker trips a warning after hundreds of charges are approved that still allows the bank to take action before the number is in the thousands of cards and makes it possible to retroactively revoke the transactions which were just approved. In the common case where someone is making purchases using stolen cards that allows goods never to leave the warehouse, and if the attacker slows their usage rate to avoid that they’re getting much less profit.
