You can see usual forex trading automation cycle on the left.After watching and analyzing charts you get some idea of a new strategy, which you can check very fast by creating EA. If backtesting report looks nice, you may demo trade it for some time and have EA for earning real profits.
Even if you have good EA, you can search for new strategies or tweak your old ones. The more profitable strategies you find, the more you can diversify your risk and make whole investment equity curve rising more evenly with smaller drawdowns. With EA Creator you can try many strategies and learn what really works for you much easier and faster.