Both have a place on the shelf. It comes down to what you want the cup to do.
Single origins are about place. A washed Ethiopian tastes like jasmine and citrus; a Sumatran leans earthy and low. They are the coffees to drink black, slowly, when you want the origin to speak clearly.
Blends are about consistency and balance. We build ours to hold up to milk and to taste the same in June as in December. If you pull espresso every morning, a blend is the dependable house pour; keep a single origin nearby for the weekend.