Usually, competitions have some rewards for the winner. Entrants join for 3 purposes:
- To win the reward.
- To "show" their strategy, so that they can attract investors to use their strategy/EA.
- To proof that they are good (which still means they want to attract investors).

However, I (personally) find that these competitions are pointless (to the people whom are consuming the result of the competition). There are many ways to "rake" the result.

Also, as it is a competition, the trading is based on a simulated environment base on price. However, it does not accurately simulate liquidity. Which means it does not simulate the price gap and execution delay, plus some other elements. Good (professional) 'winners' exploit on these missing elements. For example, a high-speed, automated momentum robot(trading bot) could do very well in simulation environment, but will fail badly in real-world. The reason being that in real world, there is a price-gap (filling of price with nearest price), while in simulation, it will always be filled with the required price (stop orders).

However, most competition-result-consumers (end users) are not aware of this and will take the result of the competition to be true, and thus will flock to give money to the "winner" to manage.