Analyzing CZ's holdings:
$BTC BTC bought by selling his house.
$BNB Binance platform token, one of Binance's revenue streams.
$Aster Bought several M tokens.
In summary, CZ's purchase of BTC reflects his faith in BTC, his holding of BNB reflects his belief in his centralized exchange (CEX), and his holding of Aster reflects his belief that decentralized exchanges are the future.
Overall, this is a true old-money approach: BTC is a safe bet, BNB represents investing in himself, and Aster represents investing in the future.