What are the pros and cons of having a main drain for an above-ground swimming pool?

The pro end of having a main drain is that you spend less time vacuuming the pool. By turning on the main drain only this will help clean the bottom of the pool and results in less overall maintenance time. Also helps clean up any chemical (chlorine, alkaline, shock, etc)that may not have completely dissolved when added to the pool. Also, when winterizing the pool, by having the main drain, you can lower the water level in the pool and still run a recirculating pattern on the filter without destrying the motor. same for opening the pool, can run the pool on main drain cleaning up the winter debris before the pool is completely full.