When we are in a casino it is always good to take advantage of every facility that the casino offers, be it a demo account, be it fictitious money, all of this must be taken advantage of so that later when playing with real money there is no complaint, that it was not made this or that because I had no way, because that's what the twenty demo was for, so there are no excuses, and obviously the feeling of remorse would be almost completely minimized, which is quite unpleasant to go through.
And add it to what you have said, most people are not patient enough to use the demo account for a very long time to master the casino before going into the real account. Some of the beginners would used only one day to practice the demo and open real account and stated using it and be losing all their funds in the games and blame other people of their downfall. At least, if you want to be professional use two or three weeks to learn the demo and when you come to the real account, you don't have to use big amount but small amount to test the casino if you can play it well, I hope those are some strategies for the demo and real gaming.