Why are dua's important?

السلام عليكم

بِسْمِ اللهِ الرَّحْمنِ الرَّحِيمِ

Allah (سبحانه وتعالى) says:

"And your Lord hath said: Pray unto Me and I will hear your prayer. Lo! those who scorn My service, they will enter hell, disgraced. "

[40:60]