Stolen bank account/fraud (Paxful accounts get traded over on bitcoitalk, too), capital controls evasion, money laundering, etc.
In other words if you are selling Bitcoins, You don't authorized the Bitcoin transaction unless you have received full fiat payment in your account. So how else will they be able to scam you if they service you are using to receive you payment is non-reversible?
If someone uses stolen credentials or social engineering to make that bank transfer, and the victim may makes a report to the bank, your bank may also learn of it. If it keeps happening to you multiple times you could get in trouble yourself or at least face having your bank account closed.