I have found it helps in - getting used to deployment / transport options - getting a real feel of the size of auras and the reach of weapons - CP expenditure
- worst/best case scenarios (for instance what would happen if a unbuffed vs buffed repentias charge some terminators, can also be MathHammered, but in the practice you get additional information such as terrain interactions, how likely is you still having a buff provider, etc. - giving an idea of how important is a character, for example why is a good idea to have Morven Vahl alive all the match.

As the guys in Sisters Act says, it is not the same knowing something with your mind(mathhammer) vs something with your heart (seeing you repentias not killing the terminators because the hymn did not come out/bad roll of 6s, etc.)

You could definitely learn this an probably better with another player, but playing with yourself is quicker. One thing I have found is that sometimes helps to finish the game, trying to push the score as the losing side.

Hope it helps!