Greater efficiency: These systems do not use ductwork to transfer the cooled air to various areas of the house. As a result, there is no temperature leakage that often occurs as cooled air passes through the ducts. This advantage provides a noticeable jump in energy conservation.
Zoned temperature control: They can be set up to independently control the temperature of various areas of the home. Each zone can have its own thermostat allowing for greater control of the temperature of the house and areas that are not used, which helps keep cooling bills lower.
This can be beneficial in larger homes so that the primary living areas can receive a majority of the cooling and the less lived in areas can be cooled on an as needed basis. This can save quite a bit on cooling costs.
Smaller footprint: These are smaller in comparison to tradition a/c units, which allows for greater flexibility for installation in your home. They can be installed in the ceiling or hung from a wall.
Safety: A/C units installed in windows provide a point of access into the home, whereas a/c ductless mini-split systems you can leave your windows closed and locked since they are not installed in the windows.