Cross trading of securities by brokers
Money management is simple because there is no leverage involved - each contract is fully margined. It is hard to pinpoint the original study where that number came from but it is believable when you consider that most successful professional traders acknowledge blowing up numerous times before developing a successful approach.
To trade leveraged products successfully you need to not only be right more often than you are wrong on direction, but must have strong money management skills.
You will never receive a margin call with binary options. The price is an expression of where market sentiment is at a given time.