For me the usefulness is more in having a simple strategy, especially if you are an average Joe investor, as most of us are: DCA, HODL and forget about the ups and downs of the market. People who use other strategies are not the kind of people who go around the forums looking for that kind of advice.
If you're investing in bitcoin, you really need a good plan whether you're looking to make quick money or aiming for the long haul.
To (try to) make a quick buck you don't need bitcoin at all. You'd better go to the casino, it's gonna be quicker.