Most people will say, “Only invest what you can afford to lose,” and yes, that’s the standard. But sometimes, if you truly believe in Bitcoin, you might go beyond the standard, just like CZ, who famously sold his house to buy Bitcoin back then.
I read about CZ selling his apartment in Shanghai to buy bitcoin at an average price of around $600 per bitcoin in 2014. But according to him, that is the majority of his assets, not all of his assets. That means that even though he has crossed the line of safety and taken risks, but he still hasn't invested his entire fortune in bitcoin.
So I think it will depend on each person's financial and other things in life, because investing is risky, bitcoin is no exception. Even if we have full faith in Bitcoin, don't go all in without a backup plan.
Not to mention, the risk when investing is not only profit/loss but also many potential risks such as theft, hacking, legal...Therefore, it would be a wiser decision to only invest the amount of money that we can afford to lose.
It was still a big risk especially if that was his major asset at the time, Bitcoin was extremely volatile back then so putting everything into it wasn't a light decision, but clearly, he was willing to take the gamble because he saw the potential reward and he wasn’t wrong. That bold move paid off, and now he’s one of the richest figures in the crypto space.