depends on whether the first failure that we are talking about gonna be draining us out of our wealth, as a beginner trader sometime just outright put out all their money into their first trading, they literally one bad decision away from bankruptcy and definitely couldn't go on continuing their trading career with no money and their "experience" gained from 1 bad decision.
but overall indeed people will get better from learning their mistake, sometime learning from book doesn't really give the impression to them so experiencing loss would teach them a lesson.
but we should know that even if we are experienced trader that has incurred loss, doesn't guarantee that we will have smooth sailing trading in the future, market is ever changing variable that gonna confuse the hell out of many people trying to profit off some small margin, or you can say, daily traders.
In the beginning there will always be losses, so it’s worth starting with a small amount, I think 100-300 dollars will be enough to start with, to identify the main mistakes for yourself and not worry too much about the money that will be lost.
This does not guarantee that there will be no losses in the future, it’s just that very serious mistakes may be made at the beginning, and in the future you will be able to avoid them. Trading is a complex activity, it seems to me that if you approach it with the proper attitude, devote enough time, and strictly follow the rules, then you can achieve a certain profit, for each of course this will be individual.