The lesson we learn from trading experience and articles we read are quite different, though the lesson from both are very important in trading but the mistakes of some beginners, they get much confidence in trading after learning only from books.
Experience gives the best lessons to traders, which beginners should never be in haste or be so confidence to trade with big amount of money by only gaining knowledge from reading books about trading.
Learning trading on your own allows you to quickly understand things clearly, but it takes a lot of time. It's true that with this time, you will gain experience, but your experience does not always determine your profitability. Even purchasing a course is not very important because most of the strategies we use are quite similar. The most important thing is to follow someone who is already profitable. You should also do a lot of backtesting.