This is really sweet news! Have you ever tried it? I personally gave up on my wireless card awhile back as I am able to find Wifi when/where needed plus my iPad with data is my backup when I must get online in a pinch.
International travel however is a whole different world. Will keep an eye not only on the idea of purchasing in a vending machine, but in purchasing this service for all of my travel.
http://thepointsguy.com/2016/12/skyroam-wifi-airport-vending-machines/