They don't need to. Use as much margin as you want and compare your ending balance to the starting balance. (I think)
I think that is the case too, can't find info on the site. It would be fun to participate as I would be one of the leaders right now, but I'm not sure what the benefit would be without a need for self-promotion. A cash prize would be more interesting.
I believe you get bragging rights. If you win or place highly in the competition you can use that to show prospective investors that you are capable of managing money. It cost you to enter and you link an actual brokerage account so you're trading your own money. No demo or sim accounts. As for self promotion it would be an excellent way for anyone selling trading courses to prove that they know what they are doing.
Minervini is killing it, up 178% so far, he has won before in the 90's. Last year Oliver Kell won with a gain of 941%. Both are trend traders using mainly chart patterns, price/volume action, relative strength, moving averages, & to a smaller degree some fundamentals like earnings growth. They also keep an eye out for companies with a new disruptive technology. They both hold winners up to months. Amazing performance - beating the vast majority of derivative traders.
In 1992, I entered Norm Zadeh's contest for UNITED STATES INVESTING CHAMPIONSHIP, Futures Division, I won with 214.7% without hedging. It was a very long climb for me as I had ended my 7th year in mid 1991 learning how to trade longer term futures, my 8th year was very much a relief, and beginning of 1992, I thought of entering. It was never for bragging, had nothing to sell, wrote no books, it was actually a celebration of me against me. I never entered to beat others, it was a way to compete against me. Percentages are based on starting capital, if you have to add, that amount is added to what you started originally. With exception of Robbins Trading group, I don't know of any other real money contests, maybe forex? However, some of past winners may have had the "bet the farm" and won like in 1987 buying options and made incredible percentage returns. The results is only about net percentage return and had no stats of drawdown or risk per trade.