Most successful traders are managing other people's money and not only their money. Which would be my recommendation to anybody who wants to become successful and rich through trading. Building a track record of a great trader is going to help to attract new clients. The benefit of trading with other people's money is that you can put on larger positions and you not only profit from when your trades are doing well. As a trader you know every day if you make money or are losing money, your positions are red or green, there is no inbetween. When trading money for other people who usually get a fixed fee for the assets you trade. This helps to generate income during bad months or when the markets are moving sideways.
Why should we entrust them to get profits from trading, why don't we just do it ourselves? I don't think that's a recommendation to become a great or successful trader from other people's money? The potential to lie or deceive the person is certain. Usually, most people who are deceived, as you said above, are people who are new to the world of investment and think that they are a quick way to get rich or get money quickly and instantly and they dare to place their trust in people who are already experts in that field. If the person is familiar with investments, of course they will not trust anyone, especially if their money is controlled by someone else.
People allow money managers to trade their money because they do not know how to do it themselves, as they either do not have the time to learn how to do this on their own or they have tried to trade on the past and failed, so becoming a money manager can indeed allow a person to make way more money than just trading with their own money, however becoming a money manager requires way more than just being a good trader, since the possibilities of getting into legal trouble if you lose the money of someone powerful is very high.