> Ross had approximately $1 million stored in two [cyrptocurrency] exchanges when he was attacked, according to a report by investigators.

You know what happens if someone tries this with your brokerage? It takes three days, not one hour, there's a name on the destination account (know your customer), it takes days (at least) to withdraw money from it, and there's a medallion signature on the transfer, so your brokerage is on the hook for it.

There's a reason fraudsters are targeting cryptocurrency exchanges: arguably less security, but more importantly, it's easy to quickly and irreversibly transfer the money.