The balloon tire bike is certainly more ornate, and was made to appeal to a teenager or younger adult, while the Sports Roadster was a more utilitarian cycle for transportation or exercise for a college student or an adult.
Both bicycles use the New Departure Model D coaster brake, which was very common on American bicycles from the 1930s-50s. Many of these "golden age" American bicycles relied solely on the Model D for braking.
The Columbia has the cushier ride with the longer wheel base, while the Sports Roadster is the more responsive and faster accelerating bicycle. Nothing particularly surprising there.
They each offer a different ride and each has its place in any bicycle collection where riding and function are key.
