I bought one of these about 5 days after posting above, and I have literally used it every day since.  Not always for a casserole, but sometimes just to keep things warm while I'm getting some other ingredient ready.  For instance, today I'm making beef stroganoff, so I browned the meat early in the day so I'm not rushed at the end of the day when the major part of the prep is due to be carried out.  I will keep it warm in the crock pot casserole dish and make up the sauce for the stroganoff, pour it over the meat and let it "cook" the rest of the afternoon.  Later today I have a couple of important errands to do and when I get home the meat will be hot but not burned, I only have to make the noodles and steam some peas and supper is ready.  I would never be able to leave home with the gas burner on my stove going, so you can see the obvious advantage to this thing. 

I love it, it's a marvel in the kitchen, for sure.  If you don't have one and don't want to buy one for yourself - - Christmas is coming!  Put it on your wish list for Santa.