You can decide whether or not your fighter will pay or train to receive attribute points. Here are the advantages and disadvantage for both.
Paying
Advantages: You can choose what skill you want to upgrade, and you can fight while still buying points, which means that if your fighter is winning all the time he will get paid more meaning he can buy more points.
Disadvantage: You have to use your money and you might ruin your record and your title shot if you keep losing.
Training
Advantages: You don't have to waste your money and your fighter can keep on getting better and better without having to fight and lose.
Disadvantage:You cannot choose which skill you want upgraded it will be randomly chosen for you and you don't get money for fighting.