On any short time frame (say less than a week), mechanical is, in my opinion, superior and has already won. It's not that machines are so much smarter than humans - but I don't know of many humans who are able to trade the same way every day. It can be personal issues, health, too much coffee, too much alcohol, etc. but in the end you fall prey to your emotions. Personally - I find even trading a system very tough. You get drawdowns, you get times when you feel the system is obviously wrong (and sometimes it is, and it's terrible). But at least you can take comfort in all the work you did testing your system, and stay the course.