The Computer Audio Amplifier or reference amplifier is used to supply power to passive monitors. They are different from a stereo audio amplifier as they are built for the studio.
If you have a Active Monitor then you won't need a reference amplifier as active monitors have an audio integrated amplifier built into them. With Passive Monitors you need an amplifier to power them.
The Reference Amplifier has advantages:
The Active Monitors advantages:
Active Monitors have the amplifier built inside the monitor which can effect the sound quality.
Low end priced active monitors are built to achieve low sale price so the amplifiers and power supplies are low quality.
Which ever way you go you will get good results.