For this reason, I think it is better to invest little by little instead of investing all the dollars at once. What is your opinion?
We make bad decisions in trading. This method saves you from losing everything. Losing everything may be worse because you may have no means to get your money back but you only lose a little amount if you and have your other part of them money. And when you get profit you can double it by adding using the other divided small amounts. Instead of demo for a long time these small amounts can be used to protect from the loss that may be encountered during that first time.
It makes a lot of sense not to use all your funds or most of it to place your trades because if you lose it you will not have funds to continue trading but if you are using small amounts from the funds you can trade for a longer time and make profits along the way. When you start to be more experienced and profitable you can start to increase your amount, no need to rush anything in trading because it is risky. It is true that demo trading will not make newbies to grow as much as they should because there is nothing at stake but if they are using small amounts it will make them to be more serious because money is at stake, no matter how little.