Usually trading with demo is actually good but for a quicker process or fast learning methods I wouldn't encourage someone to use their demo instead it's better to at least spare little money to trade in real account because Demo and Live accounts aren't operated the same way, there is much difference when you trade on both realistic accounts and Non-realistic account, you gain more life experience compared to when you are trading on demo and of course you wouldn't be that focused on demo compared to how you be careful while trading with real money, I am talking out of experience.
I think using the demo for a new trader can be an alternative method. However, no one will be able to find any Exchanger Platform for Demo Trading. But do not encourage the Demo Trade as you say. But I think this is also very effective. Moreover, my friend uses various forex trading apps, there are only BTC and eth currency pair. And my friend made a lot of money through that app. Moreover, the big thing is that there is an option for demo trading. That app is (Expert Option, Exness). Yes, it is true that the amount of focus on a trader demo, and the real trade with much more attention. However, it is possible to achieve in all cases. Whether it is Demo Trade or Real Trade.
Demo trading can definitely be a good practice for beginners, a newbie will gain knowledge from books related to trading, after that he will gain some knowledge through demo trading, demo trading can definitely be effective to some extent, but from demo I never think a newbie can gain deep knowledge from it, because he knows that he is not actually losing any money, and that is why he will do demo trading with a flippant attitude without deep research. So I think for learning purposes only, in the first stage, he should do real trading with some money that he can afford to lose, just for learning purposes, so that he can go a little deeper into trading, so that he can know trading better through real experience, and that is the most effective.