That advice is more of a psychological-related. Don't have a connection with how to win trades. It should be obvious that traders should not reach the point wherein their trading activity now affected their family life in a negative way. We should be relaxed, still on our minds, and can cope with whatever struggle we encounter while doing trades.
But not just because we are good outside trading life, it will always yield good results in the long run on our trading activities. To win with trades, we must have the ability to create a good strategy at any given trend. Being a good person just contributes that we are responsible traders despite being busy in doing trades.
If you try to avoid lose, then the profit will come automatically
In the volatile world of crypto, you can't avoid losing. Even professional traders still lose today.
What you need to do is to minimize it while building a good winning stats.
True! If a trader can't separate their work and life, then they are more likely to be controlled by their own emotions. I think it's not only about traders, it's about human! Furthermore, a trader always has to know and accept the risk of losing capital, if you trade based on the faith that you'll lose nothing, you are actually going to lose a lot more! Minimizing risk is an important knowledge that a trader should know!