It is very important to use diversification in investing, you cannot keep all your capital in one asset, because there is a possibility of losing everything. In addition, if you decide to invest in a high-risk asset, you must understand that the probability of losing your money will be higher, and if we are talking about Bitcoin, then you need to take into account its cyclical nature and in order not to find yourself in a situation where your investments lose -30% or more, choose the right one time to buy and dont delay selling, because greed can play the same cruel joke if you dont sell Bitcoin on time.
There's nothing should be scared if you invest in Bitcoin, just keep DCA-ing in anytime frames (weekly, bi-weekly, monthly etc) and after at least for four years, you will make a lot money. But, if they choose to invest in shitcoins aka altcoins, they should be worried because they could lose half of their money, most people who invest in memes are lose more than 70% right now.
Diversification is only for people who have a lot of money, say multi-millionaires or billionaires, lower than that people should go for one asset or few assets since they have nothing to lose.
