Coin actually increases the complexity of an already complex and archaic system.
The product manages to create more headaches for the consumer and the merchant by consolidating various credit cards in a digital device with a nice "cool" factor but lacking any real solution to the many problems associated with the complex back-ends in the payments space.
Conceptually, it's not a bad product, and it sucks that the founders are probably reading hundreds of people slamming their hard work. But it's reality.