Why is this such an issue with crypto?
Wealth status is often very well known for public figures and entrepreneurs. People are driving around in $200k cars.
Is it due to the liquidity of cryptocurrencies that $5 wrench attacks work better?
If you're kidnapping a generic very rich person, how are you expecting them to pay the ransom, a big burlap sack of cash? There's a lot that can go wrong there. A bank transfer or other conventional financial instrument? Few criminals would be comfortable with that approach. (John Grisham novels, and 'Archer's beloved bearer bonds, aside, it's virtually impossible to make this untraceable). Magic internet money is presumably far less messy.
Also, a decent proportion of crypto-millionaires came by their riches in... not entirely above-board ways (in particular, securities fraud; all those pump and dump scamcoins are paying off for _someone_), and may be reluctant to involve the authorities. And the crypto industry as a whole is unusually comfortable with extortion; hacked crypto companies paying a kind of bounty to hackers to get the rest of the funds back is a common thing.
They can use their bank account to buy crypto and then pay the ransom. Kidnapping is a thing in latin america before crypto became cool.
> They can use their bank account to buy crypto and then pay the ransom.
This is actually more difficult than it sounds. Most banks and crypto exchanges won't allow a person to make meaningfully large crypto transactions without some account history.
“Hey, cryptocurrency exchange, I, a random rich person, would like to, having never interacted with you before, buy a million dollars of bitcoin and transfer it out. Today, please.”
That is simply not going to happen.
Eh, million dollars would not raise a single eyebrow from an exchange side. Your bank, maybe, will have some questions about the transaction, but the things they can do to prevent you spending your money are thankfully fairly limited.
How long do you think it takes to create an account, get your KYC documents verified, get your trading and withdrawal limits raised to a million or more, transfer funds from your brokerage account, buy tokens and then re-verify when you try to transfer the tokens out of the exchange?
You'd be lucky to complete this in less than a week.
My experience with banks in UK / EU is that they will bother you for much smaller amounts than 1M. I had banks bother me for 10k transfers and other banks completely ignore me for 100k transfers.
Companies do exactly this frequently to get their hacked servers and data decrypted.
It happens with cash sometimes but people are limited to the amount they can get out of an ATM where with crypto you can force someone to hand over all their wealth with a few keystrokes.