I imagine there's a clause in the T&Cs that nobody reads about it being considered as such. Never used it (as all the cars are just taxis here anyway) so can't confirm that. But yes, it shouldn't be considered one.
Many people use cards in lieu of direct debits - I pay my cable and mobile bills...
Any service/provider you've signed an ongoing agreement with is provided the details basically. Its also how the card-cancelling trick to avoid car hire damages or speeding fines doesn't work - they are able to get the new number from the provider
Amazon at least do not use any updated details...