What are the angels? They are created spirits; they possess no body. They are quite distinct from human beings in that respect.
In some of the oldest hymns and some of the Puritan poetry which serves as hymns by Baxter and others, angels figure. They think of angels when they lie down to rest, unseen angels protecting your sleeping as well as your waking hours. And they derived great comfort from that. No communication; no nonsense or fables with angels. But the fact that they are there, such a vast force, so many of them.
Why did God create the angelic host, the holy angels? First, because he is creating God; he is by nature a Creator. He has created men and women, and set them in a physical universe, and he has created a vast host of spirit beings. Secondly, because he is a benevolent God, and it is his delight to share his work with millions, possibly, of spirit beings. He doesn't strictly speaking need them, but he creates them so that they can have the pleasure of sharing his work and his purposes with him. There are some people who don't like the concept of a working church, where as many people as possible who the Lord enables are engaged in some form of Christian service. But just look at the angels. Look at how God loves to share his labours with others. But there is another reason for angels. God must be believed in, and obeyed, and served, by great hosts of people all the time. He is not waiting until Christ returns, until there is no more rebellion or opposition to him, until there are only the saved people of God to adore him and worship him in heaven eternally. During the era of the fall, through redemption to the return of Christ, there is a vast host of angels who love him, worship him, serve him. God cannot be left understaffed, as it were, with worshippers and servants at any time. Finally, the angels show us that those who are closest to God are always learning. Learning is a great feature of godliness, the constant ongoing discovery of more and more of the wonders of God and his plans and his grace. The Christian who stops learning is in trouble. The angels are learning, and we shall be learning for all eternity.