It's very much like how cars now have electronic ignition control while older cars had mechanical ignition control with a rotating distributor. Because software controls the electrical energy inputs to the device, the timing is infinitely variable, which is generally not true with mechanical systems. Brushed motors also tend to not last as long because the internal rotating switch (the brushes) undergo constant wear. The big downside of brushless motors is that the software needs to know where the motor is in its rotation cycle at all times, but that's typically done with indirect methods (back EMF) in small motors, and with direct methods like encoders in larger ones.