Religion, as defined by the dictionary, is "a set of beliefs concerning the cause, nature, and purpose of the universe, esp. when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances and often having a moral code for the conduct of human affairs."
I believe religion has value because of the spiritual nature of man. I cannot look up at the night time sky and not wonder about the uncountable numbers of stars, and ponder upon the vast distances between them and us? There's a lot of stuff out there we don't know about. Physics laws as we know 'em, may be different in some places. There is much our current science, as "modern"as it is, doesn't begin to cover in understanding the universe. We have "faith" in our science.
Religion is as important to man as science is. It addresses the other half of our being. We are spiritual beings and strive to seek God. It's our nature, and since religion does concern mankind's striving toward understanding, it is as valuable as our other basic needs of air, food, and shelter.
Though I'm not a particularly religious person now, I was for a while when I was younger. Seems like the older I get, the more cynical I become, so this early exposure to God was good for me, and did give me a set of values that help me today in my dealings with people and with life.
Les