Seriously though, if you ran a forward test using the coin with even bet sizing, and just put a stop loss at high/low of first hour and set exit on close, I wouldn't be surprised if it outperformed 99.99% of intraday traders.
There is no real proof about the 99.99%. It is just one of the typical "oneliners" that is used. Used by people who, or never daytraded, or never where successful in it. Ask any loser in any dicipline if he believes in that discipline; the answer will always be NO. While the correct answer would be: "For me it is impossible. "
Only the happy few make money, it is the aim to be part of that small group.
On top of that it essential to try, if you don't try it is 100% sure you will never succeed.
Not all businessmen become rich or even billionaire. So it is useless to try to become one?
Ask Gates, Zuckerberg, Siegel, Bezos, Dell... if they agree it is impossible to become a billionaire.
I know that tossing a coin, putting a stop at the high/low of first hour and set exit on close will never beat my trading. All the rest doesn't matter to me. Statistics are only a valid indication of probabilities based on lots of data and can never be used to be implemented just on 1 person.
Even if 99% lose money, my chances based on let's say 1000 trades can show that my chances are much higher. Only my chances, the stats of my system, are relevant to me.
A system that does give 99.99% certainty that you will win, can end up in a loss. Even if 99.99% will win you can still lose. Only the probability is in favor of winning, but that has no value if you are one of the losers.