The Quran is the cure for the lost soul and a means of being guided and lead to good things and putting barakaa and prosperity in our life.
Reading it help us focus on the betterment of our dunya. It has a cure for everything and thus we will be granted a good akhirah, if we are willing to improve our conduct.
Songs does the opposite. They only increase the sickness and is only dunya focused and ruin our akhirah and disturbs our focus from differentiating truth from falsehood. Most of the lyrics contains shirk and words that we cannot allow ourselves to listen with our family or alone. It is a form of pollution that messes our mind.