It means you have to go to the pharmacy when it's open. That's a significant hurdle if you're sick, especially if you have something contagious and you're trying not to expose people to it, or if you work weird hours, or if you don't have reliable transportation, or if you're the primary caregiver for young children, etc....

It also means you can't get it delivered, can't stock up, might have trouble sending someone else to get it, etc.... It's a big pain for some people, and particularly for people who already have a harder life than average.