I know that some people have little faith in banks and that money in reality has no "real" value. I have also watched some huge companies (Enron?) go to the wall and Mr Ponzi laughed all the way to the bank until he was found out.
Dolllars, Euros, Pounds and most other currencies have whole countries backing them while there are no regulations governing the way Bitcoin is managed. It's hardly even newsworthy these days when some person vanishes with a few million Bitcoins or someone like that unfortunate guy who wanted to excavate a council tip to get his laptop back.
I have invested in shares, but never more than I could afford to lose. A very tiny fraction of your electricity payment ends up in my account and I have loaned some money to the government via NS&I. I do have some small understanding of how shares and Bonds work, but a currency that only exists in some anonymous individual/company account and that owes its existence to a random number in a computer is right outside my skill set.
Of course, managing the paltry few £thousand in my care is very different to the problems the likes of Musk, Gates, Buffet et al have, and their definition of "afford to lose" is a lot different to mine.
If someone gave me a free Ferrari, I would promptly sell it.