The biggest mistake that day traders make (especially crypto day traders) is believing that they have an edge over everyone else because of the charts they look at. The biggest mistake is not believing that day trading is 100% gambling, because that is exactly what it is. The only way to consistently make money over the long term is to invest based on value and fundamentals.
Only if they could end up knowing that it pays to either do short or long positions in the market than spending the whole hour in front of a chart trying to day trade.
I agree with you that day trading is 100% gambling but it is worth the risk anyway and they have a place in the market, I have been there but even though all you use is RSI or stoch to buy into an oversold market, sometimes, you may just end up missing the other indicators to know when a market is turning long term bearish, which obviously brings the stop loss into play anyway.
As an aside, I always find it amusing that in TA you can always look for an indicator or two which would have predicted the recent price move close to perfect. The problem is you would know that only in hindsight. Simply put, TA works at all times, it is just a matter of finding the right indicator or method, though there is no guarantee that it will work next time. Apart from very simple techniques like spotting a trend, for which you don't even need TA in the first place, it is mostly complete mumbo-jumbo to me. Sorry if I hurt your feelings here TA guys.