It seems every major hotel company I deal with requires me to give them a credit card number when booking a room with points or redeeming a free night award certificate?

Why?

They tell me that if I no show, they will take the points or certificate from me, they won't charge the card.

So why do they need the credit card to hold the reservation? They already have my points locked up.

I just went round and round with a Best Western phone agent like this:

Her: "We need a credit card number to make the reservation"
Me: "Why do you need a credit number?"
Her: "To make the reservation"
Me: But why? I'm paying with points.
Her: "We need the credit card number to hold the room."
ME: "Why?"
Her: "Because we can't hold the room without a credit card number."
Me: "Why don't the points hold the room?"
Her: "Because we need a credit card number."

It's the same with Hilton, Hyatt, IHG etc. I'm not going to try to fight it like crazy person, I'm just curious why.

The only thing I can think of is this: I'm going to need to show a credit card to check into the room anyway and to provide as a deposit, so it I don't have a valid credit card, they're going to want to tell em that now so I don't bother showing up. Also, they want to get the credit card at the earliest possible moment, so that if I show up and somehow manage to check in without showing a credit card, they'll have the reservation credit card on file to charge me for any damages.

I'm not sure though, is there some other reason why all these hotels require credit card numbers to make award bookings? Something I'm missing and that the Best Western lady couldn't explain?