You can go straight to God with all your prayers and needs; however, you can use this form if there is something that we can bring before the Lord on your behalf, or you are facing difficulty that you wish to have a partner in, we would like to bring it before our Heavenly Father. Not that He doesn't know, but because He said to bring petitions and requests before Him. He wants us (all of us) to talk to him. He desires a personal relationship.

"Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God." Philippians 4:6 (KJV)

A clearer translation of the same verse...

"Do not fret or have any anxiety about anything, but in every circumstance and in everything, by prayer and petition, with thanksgiving, continue to make your wants known to God." Philippians 4:6 (Amp)