That's an interesting point, but how do we get a profitable trading system in the first place? I agree with you that it makes sense to create a trading system around our profitable trading ideas. Probably most beginners have the same problem to find trades that will make money consistently. Doing research and using technical analysis is a great way to find such trades. But it also requires a lot of testing to see if our trading system is correct. Just because we make money during a few weeks doesn't mean that our trading system is profitable long term. For example, if the general crypto market moves into our favor it will likely rise all our positions, even if we didn't pick the best coins. A constant form of oversight and testing can protect us from losses, I wouldn't trust a trading system blindly just because it was right in the past.