Quote from Algorithm:
I'd argue that most traders usually start simple, then add complexity in order to try to "hone their edge", only to start stripping their methods back down in order to simplify. How ironic that in order to gain simplicity many must first overcome complexity.
Many find or at least state that MA crosses are dubious indicators and questionable as they may trigger false/weak moves, but many don't ever really explain why they believe this to be the case.
There was an extensive thread a while ago in I believe it was the futures trading forum and MA crosses were the basis for the system. One of the basic issues most there encountered was missing the move (as in by the time the cross occured and any verifying criteria were satisfied minimal profits, if any were realized) or taking too many false moves. Simply put, the chop ate them alive. Many will tell you crosses are bogus or don't work, but many cannot tell you why they will not work solely on their own (as is the case in most TA ridicule).
What I will say to you is simplicity in itself as an explanation. MA crosses reveal what HAS happened, as does all TA. As of today, I don't think there is anyone/thing that can tell the future. What may be the case though is that MA crosses are a good place from which to start a journey of understanding. You will find that MA crosses do in fact reveal something about the price action that has occurred, but to simply use MA crosses as the SOLE indicator for trading, as many others here have already stated, is pretty poor.
Good Luck!