Earlier quoted context omitted.
How is it different from all the non-secret billionaires to say nothing of all the people with 100s of millions?
Satoshi is a paper billionaire - he can't use a small fraction of his "wealth" to hire proper security. Simultaneously his "assets" are much more attractive to criminals. Imagine holding a regular billionaire hostage and demanding they give you a billion dollars. They'd probably have to sell 1B worth of stock, then convert it to cash (or crypto), etc. all of that requiring multiple interactions with different people…
They also can't easily sell that amount quickly without repercussions (and without another institution like an exchange).
You're right, but only to a limited degree.