Why does God need angels?

I'm agreeing with you...

I would argue that God does not micromanage and that He works in an hierarchical way. He made creation, and it is the privilege of His created beings to carry out His goals. God told Adam and Eve to be fruitful and multiply. Could God have just as easily snapped His fingers and instantly filled the earth with life? Yes, but He chose to achieve this goal instead by instruction Adam and Eve to have children, and those children to have even more children. In the end the earth is filled with people just as God directed.

Likewise, the angels are God's workers. When it was time to tell Mary of the conception of Jesus, it was an Angel that brought the message. Same with the father of John the Baptist. And an angel brought support to Jesus after his temptation by Satan in the wilderness.

Could God just do everything Himself? Yes, but then what was His point of even creating the universe? The universe is composed of a lot of moving parts. If God is going to micromanage all those parts, then they are not independent and are redundant.

KT