Magnetic paper can't do computations, so these tickets are a storage medium only and as such can usually be trivially copied. That puts higher requirements on the backend's availability in order to prevent fraud.

Most people in Japan actually use (reloadable) IC cards, as far as I understand, and railways seem to be in progress of switching magnetic stripe tickets for QR code based ones: https://english.kyodonews.net/news/2024/05/362243d2c187-japa...

Those electro-mechanical ticket readers are borderline lost technology and sadly don't belong in this software-eletronic era

0: https://www.youtube.com/watch?v=3Vn-QxQOoqQ

Montreal used to but transitioned to these NFC ones recently.