Lawyers.
- how much was the total? If it was over a certain amount, many will like to have proof that you authorized the use of their card.
- what was the cancellation policy?
With WDW room only pay a 1 nights deposit, the balance is due on checkin, and you can cancel up to 5-6 days in advance and get your deposit back; if you don't within that period they keep your deposit.
As a travel agent, I have to have a credit card auth form signed by all of my clients after I make their initial deposit so that they don't turn around sue me for unauthorized use of their card. Ideally we like to have it before initial deposit, but since in the majority of cases the deposit is easily refunded, getting the form signed after is ok.
If you went to a storefront travel agency or a hotel front desk, they would want to see your card and ID.
BTW, if you ever went to rent a suite that goes for many thousands of dollars per night, in many cases you need to fill out forms so that they can do a background and credit check.