I had a 2007 Chevy HHR. It had remote start/unlock. When I lived in Denver, I used the remote start during winter to warm the car up before getting in.

Also, there was something sticky with the door lock. If I used the key instead of the fob, sometimes the anti-theft system would not disarm and the only way I found to disarm it was to use the fob to turn that alarm off. Grrrr. Fobs lasted about 3 years and cost $100 to replace/reprogram.

My current car (a Miata) has a key only to unlock the door in the event of a dead battery. It has a pushbutton instead of the traditional ignition key, so the key is pretty useless outside of a dead battery.