Even if you are not earning $750,000 and you are not rich enough to put all your salary into investment yet, accepting bitcoin for your salary sounds a good deal. Some people are worried about the fluctuations in the market but as long as the employer gives you the equivalent amount of btc in usd, I think there should be no problems, am I not right? The good thing is if you are planning to put your salary in bitcoin to invest, you do not need to convert it into bitcoin since it was given to you in bitcoin already.
When you are as rich as him, you do not have to turn it into fiat, you can keep it there and it doesn't really matter at all. Because he can keep it at bitcoin ,and he can keep it there for another 20 years. He is wealthy, made millions, and if he wasn't stupid with his money (and looks like he wasn't) then he should be fine.
This is the most important part, and that is the future we live in, people will turn their investments and savings into bitcoin and will make money for the long term. He provided proof that he wasn't stupid for doing this, and even during the crash, he didn't sell and waited for it to recover and now he is in profit thanks to our bull run. He could have said this even earlier considering he made profit long ago.