I have 2 places like that near me. Both aren't 24/7 but no one knows anything about how the stores are run. One is a cafe and the other is a gelato shop.

You would think the gelato shop would be busy during the summer but there are always 3-4 guys chain smoking in front of the shop. It is so bad they had to put a walled off section in front of the shop to keep the smoke from going to the neighboring stores. So pretty sure it is a front for something