Some of them know nothing about cryptocurrency, they got here out of their greedy search for money. They just thought that Bitcoin was a way to make quick money and they end up losing. Just like my neighbor that would have ended up the same way after someone told him thy he can turn to a millionaire if he invests his whole money in Bitcoin. Luckily for him he told me about it when he got home and I made him realize that he can make lots of money from Bitcoin but he can also lose the same way, because Bitcoin or anything crypto is volatile and the price can move to any direction at anytime so you will have to be careful and not invest all you have but what you can afford to lose.
Good knowledge about cryptocurrency is needed before you make an investment, if you are only tempted by such a big profit, of course, many people will sacrifice all the money they have to invest in bitcoin but whether they are aware of the risk of the investment they make.
My personal opinion is that Bitcoin is a long-term investment because to get maximum profits it takes a long time and we have to be patient to wait for it, and you should use idle money to invest in cryptocurrency.