After playing several games I think fog offers more of a challenge and takes more skill than non fog games.
You actually need to read the game log to win and you need to deploy in multiple areas of the map to maintain control.
Most ppl don’t read the log so they don’t know who has what. With non fog games you can see who has what bonus and how territories each player has left.
Its not easy to use those cheap trick everyone talks about.
I think hidding armies is a benefit. Stopping someone from a sneak attack is classic.