Certain Promotions for Certain Battles

I noticed while playing the demo that depending on the circumstances of the battles your one unit or army has it will get different choices for promotion. For example, When battling in friendly territory the Loyalty promotion was a choice, but not Scout. If my unit or army were battling in an enemy city the Scout promotion would be available, but not the Loyalty. I would like to say that this adds nice depth and a cool dynamic to the fighting and makes sense. I was also wondering if this is just a demo thing for some odd reason and wether any of you like or dislike it.

Its in retail too & yea its pretty cool