The creed is not there to tell us what to believe, although it most certainly does that.
It's a common enough error to say that the Small Catechism tells us what to believe (the creed), how to behave (the commandments) and how to pray (the Our Father).
But the creed's purpose is far deeper. The creed tells us who God is.
Note the way it begins: "I believe in one God," and then proceeds to 3 sub-sections, if you will, of that belief. (I'm speaking, of course, about the Nicene creed). The creed, by the way it is phrased, is an explication of the Shema Israel, taken from Deut. 6.
The creed tells us about God. By telling us about God, the creed tells us about reality, about the universe, about ourselves, and much more, "For in him we live, and move, and have our being," as the Apostle Paul tells us in Acts 17.28.
The creed tells us who we worship, who we pray to, who created us, and who commands us what we are to be and do.