demo is very much important for all kinds of trader , but the main problem is when trading in a live account actually demos performance not works actually.
Everyone wants such a trading strategy but making such a strategy is time-consuming. So, invest your time in trading and stay watchful of the market condition.
Your knowledge will help you develop good trading-friendly mindset and think strategically. Whenever you have a strategy, apply it first on the demo account and then judge its effectiveness.