It helps to know. For instance teams that play with a defensive mentality tend to dominate the game especially if they are weaker. once I notice that my opponent has set his team mentality to defensive, I have a set of orders that I use to counter this and it works 95% of the time.
It's very important for me to know the mentality of my opponent given that I'm usually the strongest team in my league, so most opponents switch to defensive when they face me.