The payment processor, Nets, is a monopoly, owned by US investment firms. They have frequent outages and are unapologetic when they do. There is no transparency. They have a terrible privacy record (see https://en.wikipedia.org/wiki/2014_Se_og_H%C3%B8r_media_scan...). Until last year everyone down to their phone support staff had open access to everyone's payment records (see http://www.computerworld.dk/art/230818/alle-kundeservice-fol... -- in Danish). Despite all these issues they just laid off a bunch of people. Their only priority, it appears, it making money for the owners.
Money is a critical piece of infrastructure and these guys absolutely cannot be trusted to implement it. With more payment processors and a regulatory framework that forced them to provide decent service maybe cashless is not a bad idea. With the current implementation though there's a good chance it will be a disaster. It will certainly be a gaping vulnerability for anyone who should feel like targeting us; I wouldn't be surprised if all it would take to bring the whole thing down is one lone hacker.