Cell phone based remote starts handy. I can start the car while out of fob range.
I really only use the cell unlock when I forget to grab the key to get something out of the car. I could walk back inside to get the key, but it ain't worth it.
Skiing is the most common case for me. On my last run, I'll typically get the car going while I'm on the lift. That means it's ready to drive (not just pre-hot) when I get my ski gear put away.
I think my wife uses it sometimes at work. She's on the far end of the building from her vehicle, so out of range of the fob.