Just imagine if all of us knows how to use RSI and MACD. We all know when it is overbought or oversold. Therefore, we already know as well when it is good to enter and exit in market. Since we all knew about, RSI is not a good indicator anymore and many of us will find a new indicator that will provide us more details than the latter one.
Now, many Trading Gurus are teaching the best strategy to use. Wherein fact, strategies are becoming obsolete as time goes by. If you are new in trading world, definitely you will be eaten by those traders who know a lot in trading.
I believe it's cyclical. If a trading strategy has become very popular, its effectiveness will be not as much because the trades taken by such a strategy will be "over-crowded", and over-crowded trades will have a lot of "counter-trades" in the other side of the orderbook. Once the trading strategy's effectiveness is not as much, its popularity will become lower, and once it becomes lower, it's effectiveness will go up again. A cycle.
Overbought and oversold strategy is very popular, many traders indeed use it on the longer time frames which I believe works best that way like the weekly chart. The more traders use it, I think triggers a bull market especially when they all buy at the oversold level and hold it.
Using the strategy on leverage trading is what I actually wanna try more but I don't have the courage to do it all the time so because I'm too scared to lose quickly when the market goes in the opposite direction.
It's very popular, and often causes you to make the wrong decision during strong or weak markets. "Wrong decision" in terms of selling too early. During bull markets when the surge is strong, many "traders" who strictly follow Overbought/Oversold oscillators have the tendency to sell early because when RSI reaches 80, they sell. But the price continues surging more. It's probably also the same on the opposite direction when the price is crashing.