On my last two quickie trips to Caesars Palace I ran into problems charging anything to my room.
First time it was an unplanned overnight stay. At check-in, instead of giving a credit card, I used the option of giving a $200 cash deposit towards room charges. However, when I got up to my room I discovered I could not watch a movie or open the room refrigerator to get a soda, etc. It seems that without a credit card, you have no access. The $200 deposit is to cover "incidentals" but not expenses such as movie rentals, room bar, room service, or restaurant charges. I told them I was Seven Stars and entitled to a free movie -- but still they wouldn't release the movie rentals because I might watch more than the one free movie I get with Seven Stars. So, I called my host who had them release the movie rental.
Second time it was a planned overnight stay, but I didn't give them a credit card but my debit card. The Seven Stars check-in person said nothing to me, but that evening at The Old Homestead Steak House I found out I couldn't charge to my room because a debit card was not considered to be a credit card. So I actually had to pay the check in cash and then... I had to march over to the Seven Stars check in and give them a credit card to use. However, at that point I was angry because I wanted to use my Reward Credits to pay for the dinner. So I told the Seven Stars manager to get me a CASH refund from Old Homestead Steak (which they did do and gave me cash a few minutes later) and charge the dinner to my room (which they did) to the credit card they now had.
Now... a few months ago I stayed at Bellagio, and I gave Bellagio my debit card and I had no problems charging anything to my room including some meals or watching movies which I had to pay for with either comp dollars or cash.