Maybe because it is very complex to convert the money from crypto and it requires KYC where personal details are required before getting the money.
So they prefer the traditional thing and besides not all of them are capable of hijacking cryptocurrency.
It's obvious that it's easy for criminals to use the traditional which has easier transaction processes.
besides being easy, the value of Fiat is also more stable. different from crypto which is very volatile. for example, today the thief gets 1 million dollars, when it is stored into crypto, the next day the asset value can be 0.99 million dollars, because the asset value is difficult to predict.