Not using a Demo trading account is considered a form of arrogance, and thus a trader will end up thinking that he understands everything about the market and suddenly loses everything. Therefore, as long as you want to trade, learn from everyone, listen to everyone, and try your plan in Demo accounts, and then you will get a better vision than investing without thinking.
There are uncertainties in cryoto trading, because of the risk of loses, therefore it is not a bad idea to have a demo account to try new experiments. Especially for newbies in trading, they need to start with demo accounts, to familiarize themselves with the outcome of readings, how easy it is to lose everything in a very short time.
The usefulness of a demo account is limitless and what you use it for might not be what others are using it for. For the new traders, it is a very good means of learning the market risk-free and will still afford them to know all the necessary things that will make them successful in it. For the experienced traders, they might need the demo account to continue to upgrade what they know in the market and even learn extras when they deem it fit that using the real account could cost them a lot.
Till now, I continue to use a demo account despite having many years of trading experience and I have never seen a reason why I will not continue to use it. Because as I earlier said, the usefulness is limitless, and it's until a need demands for it that you know this importance at times.
Although the disadvantage of demo account will be that the traders using it might not put in the seriousness required for actual trading, because even if they lose, it won't be real coins. So if a trader has to use a demo account, let him put all the mental work that real trading requires.
I knew you would say this, but to me, it's not a disadvantage of a demo account, but rather an issue with the people who use it. Even though you called it a disadvantage, there are still many people who are serious about it, so we should not down-talk it simply because people do not use it as they ought to.
So, it's left to anybody to learn and train all that is needed about trading effectively or beating around the bush. Either way, they will reap the result in live trading either good or bad. The choice is ours, the demo account will do all it is supposed to do.