AFAIK this is true if you have the various 'plans' on your personal (yellow) card, which comes with additional cost. The 40% discount is there with one of these https://www.ns.nl/en/season-tickets/
That's super helpful, thank you. I guess for most people not using subscriptions the main reason was the automatic saldo, but now with mobile pay that's not an issue. No need to get your money back either, though I was under the impression that this is now also possible with anonymous cards.