Define actually useful applications. Also, maybe it is possible to do so? Furthermore, given that this possibility exists - which I'm pretty sure it does - I see a glorious task ahead for you. Yes, you, dear keyboard warrior, are given the mission to develop such an actually useful application to teach those hicks with their $hitcoin mine running off gas which would otherwise have been flared off how wrong they are. Design and build that actually useful application, install it and show the world.

Until such a time I'd say they did quite well with their mining thing, given the circumstances.