What is the significance of the law requiring lawyers to defend murderers?

According to Article 37 of the Criminal Procedure Law of People's Republic of China (PRC), the responsibility of defenders is based on facts and laws. Put forward the materials and opinions that the criminal suspects and defendants are innocent, the crimes are light or their criminal punishment responsibilities are reduced or exempted, and safeguard the litigation rights and other legitimate rights and interests of the criminal suspects and defendants. He shall not be found guilty without trial by a people's court.