Maybe I "don't play the game correctly," but while I enjoy immersion I still tend to drive toward accomplishment in FO and TES games. It's fun to kill some time gambling or playing other mini-games, if for no other reason than to know it's an option, but I just don't revisit these things often when the gains begin to stop representing the effort and time.
That being said, I would totally play a standalone Caravan game. In my life, my iPad has all but replaced my laptop. I still use my laptop for remote server access (for work), to write at length (Scrivener), and for audio recording, but I otherwise the tablet for most day-to-day activities at work and at home. I think a Caravan app would have done exceptionally well had they released it among the marketing for New Vegas. I would still pay a few dollars to have such an app today. I thought the game was well designed and accessible to most casual card players such as myself, and I think it would be a lot of fun to have on a tablet.
What do you think? I know it won't happen, but if a standalone Caravan game existed (android, ios, even "full-size" windows/mac), would you play it?