The air conditioner fan will serve to circulate the air, and may serve to reduce the amount of time you need to run the compressor. The compressor uses far more energy than the fan, so if you find it comfortable, do so.
Running your air conditioner fan all the time is inefficient and will lead to large electricity bills. Use a programmable thermostat to help save money.
Its not necessary for an air conditioner fall to be running all the time, unless if room is properly protected by glass to prevent leakage. if the room is open completely the A/C will be wasted so the fan has to run all the time no other goes.