well to be honest i don't think machine learning which is popularly known as Algo trading is not profitable for long term. Algo trading is a automation process of strategic system which is prepared using a set of rules and algorithm.And by the way i always recommend people to go for Manual trading than Algo trading, as Machine Learning cannot match the Manual  process when the bitcoin market use to change dynamically with rapid shift in time. If at all you are doing it, i will tell you to look for traders who are having more than 5+ yrs of experience in algo trading.