I have never worked out the answer to a wondering: Why angels? I suppose though you could ask the same question of any or all created things. I guess like all things, angels were created for God’s pleasure and for His glory.
Part of their God glorifying purpose is to minister to you and to me. I have one who looks after me and looks upon my Father’s face with me in mind, and so do you. I have met my Guardian angel, to use the common phrase. “He” never said a word. We simply exchanged glances. He did the miraculous deed and left the scene. To speak to one another would have been to steal the glory of God and take some to ourselves.
You have probably seen yours too and never realised it. No matter really. Oh, I know we are not to go into great detail or get puffed up by such things, but that does not mean we fall into the error of discounting them or despise any talk about the angelic at all. That would be ungrateful and unthankful for the faithfully completed assignments of these ministering spirits of fiery swift obedience. Maybe one day in eternity as I heard a preacher say not long ago, we will sit and talk with our Guardian angel, look back over the replay of our lives as he/she (?) says time after time, “See that? I did that. Your Father sent me do that for you. I was watching His face below the veil of my wings, and then I saw the gesture of His hand, heard His command, ‘Go! Go now! Go swiftly! Fly faster than the wind, burn with zeal to do my bidding! Go!’ “…and together we will praise the One who lives forever, give Him all the glory. He may cover his face with his wings. I will fall down.