This is like a trial error so you know what the advantages and disadvantages are. Some beginners really need it and some don't need it at all. this depends on their courage. If you face a real market it will help build trading psychology so that you will be better prepared to trade larger amounts.
We don't need to enter the market immediately after we had lesent how to trade and make profits from the market. The best way to master trading is with the use of demo account. It lose like real account but we don't have to be too relax as a trader that is in the market. We need to demo trade like we are using really funds and this is the only way we can make profits from the market.
as we put it, everyone is free to own their demo account, whatever it may give him as an advantage in the actual trading market. but your expectations should not be the same as the market performance is very different when it comes to real trading world.
you can always practice your new strategy in your demo account but the actual, you would have various factors to consider as you don't know what their developers are planning for their project.