Putting everything into crypto for me is not the right thing to do. It's a good thing to divide the coins of several groups in a portfolio and many have had success doing so. In common sense, what will we use when we need money suddenly if we put everything in there. At least there should be savings as an alternative when we need it.
Yeap, putting everything into crypto it's not an good choice as you said and maybe splitting it by buying some stocks and make an good portfolio, people need to manage their money wisely but divide it to long-term or short-term investing beside that savings money for urgent situation, We never know when we need money so it's good choice to put some money on savings especially on bank, Beside that gold it's another good choice since it can easily to convert on any place.
It's really recommended to diversify portfolio of investment but in my opinion people with investment might already have their own money for their basic needs.
That's why when it comes to investment it's always recommended to fulfill basic needs like food first then invest in stock or crypto so they can choose to invest long term or short term.
But having investment like in gold where it's accepted everywhere is also can become a solution as you mentioned since many people are always trying to buy gold and there are many demands for gold everywhere, But in my opinion it depends for everyone on how they diversify their investment portfolio.