Not very. And yes, no magic - just calculated risk. It is almost guaranteed that by tomorrow my profit will be 0.01-0.02 BTC higher than it is today. I am saying this openly and in public, and the proof is in the link I gave. Just see for yourself.
They key word here is "almost".
And the big question is: what's your bankroll? It's very likely to go up a small percentage of your bankroll. Until you bust, as all Martingale will eventually do.
I obtained the exact same results from the same tool, copypasting in the script with no trailing newline:
I've had similar problems with online hashes when I tried to do that for
md5sum.