What does flour do to cheesecake?
Flour or starch binds moisture in the cheesecake. 

If you use it or not depends on your recipe, the total amount of liquid and the other binding ingredients like eggs.

Using flour can leave an aftertaste, especially if not fully cooked. I recommend using the more neutral starch (corn starch, potato starch) instead.

As a rule of thumb, adding starch or flour can make the cheesecake denser and more solid, leaving it out makes for a softer mouthfeel. 

Disclaimer:
I am not saying that you can leave it always out, lest you come back and blame me if your cheesecake doesn't set properly. If you have a recipe that seems quite solid, you could experiment with less or no flour next time, likewise a recipe that is too runny can benefit from a tablespoon or two of starch.