"Bitcoin transaction is irreversible". I would have loved it to be, but there are reasons why it's not. Also, a transaction that was made from one bank account to another is irreversible too. So it's not new.
I want to correct your statement, bank transactions are reversible and it's simply possible with a single click from the banking side and the common term we see is chargeback. Whereas in Bitcoin the transactions are impossible to reverse and the difficulty becomes higher and higher along with number of confirmations so how can you say it as bad thing?