Let's face it - the air ducts that in our most of our homes are just horrible places to look into. Filled with big clumps of dust, hair, fuzz, and unhealthy particulate, most people pretend they never saw inside of a duct (if you happen to be up next to one changing a filter, or otherwise). They serve a simple purpose - to transport air from your heater or air conditioner to each room.
But central HVAC systems make the whole house the same temperature....even if you're only in one or two rooms at a time. Think about it - from the time you come home, the average person is only in 3-4 rooms, and not all at one time. And yet you spend money and energy (and valuable resources) to control the temperature in the entire house.
Most countries in Asia have long-ago adopted the ductless mini-split system. Having a heating/air conditioning system in each room allows you to control the temperature and climate - where you need it (and not anywhere that you don't). This allows you to save money, be more efficient - and avoid the need for those dust-bunny filled air conditioning ducts.
The systems are quiet, fade away on the wall, and easy to operate with a remote control. Plus they cost the same (if not less) than standard central HVAC systems.