Yes, I used a demo account when I first learned to trade, and before I didn't know Binance and other exchanges, one of my friends asked me to trade on one of the platforms, but it was very difficult to trade on that platform, after I got to know crypto and the first market I knew. I know Indodax (local) for global Yobits if I'm not mistaken
I think most traders have used a Demo account when they first enter the financial market because everything is quite complicated for newbies and they are all afraid that a mistake could make account/balance disappear, or they were in a hurry to understand more about technical analysis methods that they have just heard from KOLs ^^
Currently, all CEXs have Demo accounts, even projects/companies in the crypto market also provide this service to users. It is easy to create a simple portfolio to track the real portfolio or Demo portfolio on Tradingview, Coinmarketcap, Coingecko... Perhaps crypto traders no longer need to create manual trading journals on notebooks or Excel like many years ago!