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.
Not all writers of books, articles about trading tips are successful traders based on the experiences they have had. They could have written because of other sources to be used as an article and not because of trading experience.
You are right that the trading experience itself that is done consistently is a very valuable lesson.
Reading articles or writings that someone can get a lot of money because of the trading they do can hypnotize our minds and give rise to a high sense of confidence that we can get money in the same amount as them. This is the beginning of a trap that will determine two outcomes, safe or lost.
It can help to learn something from others, however, the main teacher of a trader is the market itself and his own experiences of it.
Sure, sources can provide different theories and info, but in the end, you utilize it in your own way.