I think it's because GP mentioned "PoS software" which is often used by cashiers, but is not limited to cashiers. Anywhere a user might swipe or tap their credit card could be considered a PoS.

As a related aside, I recently visited Microcenter where they run their own PCI-compliant PoS system that's all text based. The staff all knew how to zip through various text menus to apply discounts, warranties, etc.