Long term or short term, both can give you profit. if you choose short term, that's sure you can't get more profit, you just earn the little profit. But if you choose long term, you can earn so much profits from them, although you must wait for the long time, but it's fair for me.
Considering how the market works better to say that theres no assurance to make profit both on long term and short term. The risk are high but if you are willing to take it Im sure its worth it. Always know what strategy you will use to prevent big losses.