I don't blame them. Yes, there is big money to be made through crypto, but even after reading the book, I get the feeling it's a very risky business. Possibly invest small sums to see how it goes?
Trouble is, for those who have capital savings, the usual safe haven of a building society ISA is increasingly a loss maker with pathetic interest rates and rising inflation. Thus ongoing real terms depreciation of cash holdings.
Best to invest in something else - maybe gold via the Royal Mint. Has a great track record over a long period.
Property if you have the money, but you'd be buying in an overheated market, and buy to let seems somewhat deleterious to the interests of landlords these days. That programme "Nightmare tenants, slum landlords" is enough to fill any potential landlord with horror.