So, yeah, this product is a bit confusing until you realize it's just meant to be for application development. The whole idea is to build services that people will pay you for, that are served off of your personal 21.co machine, that or to purchase the services that are being offered. The mining bit is just meant to give you a small stream of bitcoin to mess around with.

This could all be done with your own server or whatever, the 21.co machine just makes setup easier.