To speak of why people need and want art and design is really a conversation about beauty and emotion.
Beauty gives us hope that just around the corner, we will have it again. We will experience rest, peace, surprise, joy, love. Seeing glimpses of those things in other humans reminds us that - oh yes! I have felt that before. I will feel it again! I believe! Beauty is faith made sight.
Beauty and emotion are really conversations about contrast. Because, what is joy if you have never felt opposition to it? Beauty, joy, love, life all exist as a thing we experience and notice because they are resisted by something. Ugliness, depression, hate, death, confusion, betrayal, loss.
Art and design want to illuminate the contrasts. Art and design thrive on variation. Highs and lows, hards and softs, uglies and beautifuls. The minor suddenly thrown into the major song. The relationships between these pairs become beauty themselves, perhaps of the highest order. The response of a human to this contrast cannot be achieved in any other way.