Got my adorable vintage Mickey one a couple of days ago! Love it!!
And I almost yet AGAIN blew my DLR trip surprise and almost blurted out to my DS about how I'll get discounts at
Disneyland when we go...

I only have two more months, thank goodness!! The look on his face is going to be worth all the biting of my tongue in half, lol.
Back to the debit card, I also received the big "deposit agreement" thing, but didn't read it word for word. I've been with them for a bunch of years, and like you said, this was just replacing my old Mickey debit card.
One perk I wish they offered along with the park perks -- some sort of discount in the ship shops! I know you couldn't actually pay on the spot with your card, but you could maybe just present it for a discount or something. Or they could give the $50 OBC for currently booked cruises.