As part of the no crate minority . . . I see no reason to introduce crate training here. If your pup is non-destructive and relaxed with freedom of the place, he or she will be fine in the car without confinement, and more comfortable unconfined in the apartment than confined. If you're worried about safety travelling, you can work on things with straps and / or barriers, or simple training to keep the dog in the back for times the car is in motion. Crates are a PITA. They make it hard to vacuum or mop floors. They take up space. My dogs are much happier on the couch, where they can snuggle up and get their butts scratched!
Thank you for the input. I have to use a crate for the car as it is part of the rules of the carshare I am with. We are also likely to stay at friends or relatives a few times a year and I'm wondering if having a familiar 'bed' in the crate would be more relaxing, especially around other dogs? If I didn't need a crate for the car I don't think I would even consider it?
I think I've answered my own question AND totally confused myself :p