It's not always enough in case you want to become successful trader. I believe the matter here is to have an ability to learn and practice properly. It doesn't depend only on demo trading. It depends on your ability to digest new information and collect and gather information. In my opinion, traders have to understand that everything comes with the efforts. The more efforts you make, the more chances to become successful you have. Some traders prefer not to make efforts after several fails, while I advise traders not to give up and continue developing their skills even despite the fact of several fails. They shouldn't break you down.