It doesn't cost the WT anything but slave labor without electronic transfers, most electronic transfers have fees charged to either the recipient or the sender. Think how many things you have automatically deducted. Then go look at your bank and credit card statements. Do you still want or use all those products and services? Probably not. For a few bucks a month, you might not care enough to bother cancelling a magazine or charity or some membership or another. You tend to go along with the status quo. They count on it.
Getting your bank(routing) info vs your card numbers mean that you won't revisit your decision every time you replace your credit card. That's great for mortgage and trash services, not so much for optional, variable services. Don't have anything come directly out of your bank unless it is critical for your life. Putting things on debit cards that expire gives you a chance to revisit your choice or simply drop it when you don't update it. Helps one avoid having money sucked up into places you don't need or want.