[dqv]

It only works if you have an active account with the issuer. It's simply a convenience feature for subscriptions to go to the new card since it would be rather annoying to have to go through 20 different subscriptions to add the new card.

[pc86]

I actually viewed this annoyance as a feature. Wait for the Dunning email and either log in to update or do nothing.

[dqv]

That's fine. Most people don't want to have to re-enter their new credit card everywhere, so you can always call your issuer and ask them to issue a new card, but stop all subscription charges.