If a startup is able to reach profitability within three months, this startup surely wouldn't need Mark Cuban's money to move forward and create jobs at some point in the future. They would have a rather big chance at succeeding even without this extra cash.
Mark presents this initiative as doing something for the greater good and the economy, however investing in companies that need to be profitable within three months (assuming funding will stop if they don't reach profitability within that time frame) is not exactly a risky investment and looks more like an easy way into something new for Mark.