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.
Although it is true that people in general learn faster and more effectively by doing something rather than just reading about it, any person that is thinking about becoming a trader or an investor cannot really afford to take this path, and the reason for this is that it is very expensive, so an aspiring trader needs to spend as much time as possible reading books and fine tuning their strategy, this way whenever they finally decide to trade for real, the number of their mistakes will be significantly lowered.