"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?
But it's not easy for you to convince the bank to help you get your money back once you've sent it. If it's just a small amount, you won't have a chance to get your money back after transferring it to someone else. If it is a large amount of money, you will certainly have to present a lot of evidence and ask the police to intervene and you will spend a lot of time waiting for the bank to process it. In general, I think getting your money back in a banking transaction is not simple if the error is on the user's side.