Cool or fun for who? The user or the startup? For the user, cool fun entertaining things solve a clear problem, boredom, and ease a pain, the fact that they aren't as cool as other people in their life, and the product can fix their dissatisfaction. Keeping up with the Jones's and boredom are very valid problems and drivers, and an early adopters desire to have the greatest and latest tech to show off is a real pain you can assuage.