I have always charged everything to the room key, never had a problem.
On my trip a couple weeks ago with friends, the room was in my friend's name (she's a TDS castmember and got us 50% off) so I had to use my own credit card or cash. I really missed the room key charge. We put our meals on one check to get her cm discount, so I had to have cash for most meals. I don't like having my credit card # floating around "the world" so I used cash as much as possible. For the first time, I had to go to an ATM and pay a fee.