Greg Burkart :
Any reason for the limit of 5 training games per day?
To answer your original question, it keeps people from just spamming map games all day for cash/training points (which is what I would do) or to constantly hold a high rank (which is what the best guys tend to do).
As for Whiny McGee that spends all this time complaining about a game but keeps playing, have you tried spacing your games out and using them in retaliation to gain rank/fans back after a loss instead of just whining?