Is because the Apple pay, and etc, pay devices at our mobile, works with RFID, a technology that makes our phone pay wirelessly, and in Rejsekort they use, NFC. Here comes so the why it would work, and mostly because RFID has as first a longer range to sends there signals out, and NFC has a much smaller range, RFID has around 100m range, and NFC has 10cm, which also includes that the Usage frequently is also bit different from each other, that’s makes the difference between those too, RFID is also one way contactless communication, and the NFC is two ways, and that’s also why, they maybe haven’t implemented the rejsekort, for the phones, in the pay services apps, or what you wanna call