What is the key used for in a 2013 dodge jorney sxt

I'm guessing you have a proximity key (push button start). If you do the key is for the drivers door lock. If you have a dead battery in the Journey the key fob or proximity won't work. You will need the key to get into the car and pop the hood release so you can jump it.

But what if your car battery is fine, the key fob battery was recently changed, but sometimes will not unlock the car. But if it does, the car states the key is not identified. How do I start the car?

When this happens try using the rounded end of the key fob to press the start button. Main car battery may not have enough charge also. To limit battery drain, turn off passive entry feature.

How does using the fob help

I don't know how.it helps but it does..we just had to do it this morning.