Our last two pots have been Krupps. They both have had the thermal carafes that keep the coffee hot for at least 4 hours. And when I say hot I mean hot as if it had just been brewed no more than 10 minutes ago. We never pre-heated the carafe, but I have no doubt that if we did then the coffee would have stayed hotter hours longer. I have done that before with other carafes and it really works.
I am not recommending getting a Krupps though. Our first one was great and I would have happily recommended it, but this new one stinks.
As for why anyone would want to keep coffee that long, My wife wakes up hours earlier than me on the weekend. She makes a pot of coffee and has hers. I wake up 2, 3, even 4 hours later and can go and just pour my cup. It takes exactly as if it were made that minute. It is a great convenience.