Landromatch - The coinless App

This idea came me out when, after several times, I forget that I had to have some coins to do the laundry since the machines only accept small pieces.
So, why not have those machines connected to a payment service where you can pay beforehand? Upon that, we can also check if there are available machines around you and book it. What a lifesaver!
Oh my gosh! I want this app now!
And you, what do you think about this idea?