The premade approach may not be suitable for all traders. So, in order to establish a successful trading profession, strive to devise your own approach. If it works, it’s good, if not, go to a demo account, tweak the strategy, return to a live trading account and implement the strategy. The point is to keep trying until you get it right.
In my opinion, the demo is necessary for developing a trading strategy. Those that enter with money early due to the psychological component of trading with real funds, in my opinion, are missing the point. You'll still lose if you don't have a decent trading plan with risk management. To encourage positive behaviours, I handle my demo accounts as though they were real accounts.