As others have pointed out, those discs are only for free time-limited parking in Denmark. Some places have parking meters. Those places often use a mixture o

As others have pointed out, those discs are only for free time-limited parking in Denmark. Some places have parking meters. Those places often use a mixture of physical meters and the option to use an app. The physical meters aren't next to the parking spot, but rather nearby. They ask you to enter your number plate, and they only take payment cards (no cash). The apps are similar, and you can use one of several apps, issued by several different private companies (who also maintain their own parking spaces). Some places, however, finding the nearest meter, or payment machine to be more accurate, can be a bit of a trek, so it's not super convenient, if you don't use the app, like me.