Colossians 1:10

so as to walk in a manner worthy of the Lord, fully pleasing to him, bearing fruit in every good work and increasing in the knowledge of God.

-Colossians 1:10

Here in verse 10, we get to see why Paul is "asking that you may be filled with the knowledge of his will in all spiritual wisdom and understanding".  He explains that the purpose is for them "to walk in a manner worthy of the Lord, fully pleasing to him, bearing fruit in every good work and increasing in the knowledge of God."  I guess this means that to know God better is helpful for living in a way that is worthy and pleasing to God.  It is also helpful for bearing fruit and increasing in the knowledge of God.  This shows what is important to Paul, namely living in a way that honours and pleases God.  It's all for God, and living for him is should be at the forefront of our lives.