First off, you've to understand that whether EMA or SMA; both are "Lagging Indicators" and as such they only react after price and not before price. They only take decisions and directions after price has gone through. It's the opposite of what Pivot Points, Support and Resistance, and Trendlines do. The latter get there before price and the trader is already aware of what is expected when price hits them. On few occasions, I've used SMA and that's on the higher timeframe of 4hrs/Daily and on the 200 setting. I used it to gauge trend. That's, change in trend. Since it's a lagging Indi, it has its shortcomings because it doesn't always show accuracy. BTW, the SMA setting of 25 is the same thing as Bollinger Band of 25/2.0. So, you see that most of these indicators are related and that's why I don't use any in its default state. If you must use MAs, I advise you choose higher timeframes so as to sieve out the noise.