The joys of single supplier most likely. Probably contracted to provide 1 mil a year or something then if tourism greater than that have the "disposable" ones... doesn't need to be any hardware difference though a simple time limited cards get activated with expiration date and server auto permanent inactivates them.
yeah they still have the ticket stations next to the one to refill/buy IC cards. and thanks to the 20/21 Olympics in english now too(not 2 levels of menus deep like many of them used to be) so pretty easy to do