What's good with demo trading is that it allows you to practice your entries and exits, assess whether you can identify the patterns and eventually familiarize yourself.
Demo trading is basically for learning the interface and its capabilities so you don't get surprised by it. That's indeed a rather limited use, still, I would not call it waste of time.
On the other hand, trading is for people who know what they are doing and some may need practicing. I see no harm in that.
even if it is 1$; feel the heat and develop instinctively.
This is imho a bad advice. This would make people believe that trading is some sort of gambling,
and it's not.
Trading needs clear mind and good strategy, not instincts, no haste decisions made when one "feels the heat".
One need good thinking, fast hands (or trading bots), and patience.