I'm looking at charts of bitcoin here: https://bitcoinwisdom.com/markets/kraken/btceur with the option of displaying a short term as well as a long term EMA.
It seems to me that if I were to buy bitcoin each time the short term EMA raises above the long term EMA, I would make money. I know this is obviously not the case since if it were, everyone would do it.
So in reality, what actually is the problem with these kind of simplistic strategies? The "strategy" seems to cover every relevant change in market price.