The only thing a stop loss is going to do is get your order filled as the hedge funds controlling price can likely see the prices where stops are concentrated. That is indeed what happened to ETH last week. "Luckily" for those who did not use stops price recovered to $350+. The otehr problem with stops is that there is a very small window for sell orders to get executed through. Because the exchanges are so inefficient they might only be able to handle 25 sell orders at any given price out of the 250 orders that have had the limit sell triggered. In a fast market selloff, if price stays doooown, it is conceivable that someone with a stop set at say $250 on ETH would have ended up with the $13 if that's where price stayed until the Chinese mining machines matched up the buyer and selller. Crypto trading is certainly a way to eliminate your wealth very quickly as many will find out soon I'm sure.