> When someone does a bank heist USD doesn't get devalued

This is a bad comparison. If a bank experiences a sizable heist, their stock price will probably fall because shareholders eat dirt before depositors. Such explicit seniority doesn't exist in the cryptospace, however, so depositors would probably eat dirt alongside the exchange.

What you said still doesn't make sense. Binance coin lost value accordingly, why would the underlying asset stored in the bank lose value?