Using a demo trading account gives us an edge while we are starting to trade, but we know once we enter the real trading market, everything should be learned all by yourself. And the more real experiences you gain, the more likely you will win your trades. And with this, I think demo account will not be sufficient enough. One should learn how to trade in its real scenario, otherwise you will never experience controlling your emotions at all when trading.
Demo doesn't actually feed us with our expectations on live accounts. That's the main deal, we faces the market with our own money and miminize the lotsize that's convenient for our trades, which will either end on profits or losses. Experience they say is the best teacher, we adapt to live trading only when we mastered how to control our emotions and balance on the market. Trading with the demo accounts grants us self confidence specifically when we triggered TP on our trading positions, but basically demo helped the newbies become more acquainted with trading systems. Demo is really good in backtesting your strategy, and you really have a point on the experience or how we feel when using real money, but again, this is up to the people if they want to risk, as others still don't want to risk their real money. They want to have established their strategy and wait to see if it is profitable. This is called playing safe, which they learn in this kind of method, but to others they tend to learn from experience and losses. That is why if what ever works on you, then you go for it, as we have different ways to learn.
