Is Forex Trading Hard

Is there a catch or scam in the demo forex accounts?
So I’ve been playing around with forex trading on a practice account with $50k. I was able to make over 3k on a successful transaction. And I can make at least a few hundred on each transaction. And all that is in a matter of hours, sometimes minutes? It’s hard to believe that those practice accounts are the same as real account. I mean I turned 50k into 55k in one day on the practice account? That doesnt seem realistic. Can anyone explain me what’s the catch?
The catch is that you can loose 5k or more in a very short period of time too.
Exchange rates go up and down every day. And anybody can make money once in a while in Forex trading. But to be profitable in your trading over weeks and months you need to avoid loosing money. And to avoid loosing money over the long term is very, very difficult.
Forex Trading #7: Don’t Learn the Hard Way “The Gauntlet”