If you are a musician you probably want to show your work to the world.
Every musician and music band dreams about a record and some day listen their songs on the radio.
So you surely want it sounds as good as a pro.
Mastering allows a song has a commercial sound.
Mastering balances the tone of the song.
Mastering gives the proper level and color to a song.
Mastering makes a song brilliant and sparkling.
Mastering polishes a song.