The first benefit you get from accepting bitcoin is that you gain more business as you are offering an additional payment method. For those people who want to do transactions in bitcoin, they will prefer your business as compared to those who only offer traditional payment methods.
Also, when more people will integrate bitcoin and allow bitcoin payments, other businesses will follow the same and a time will come when most of businesses will allow bitcoin as a payment option.
It's more than that. Bitcoin transactions are irreversible. So when you as merchant have received the coins and the transaction is confirmed, you know the money is in your pocket.
On the other hand, with banks and cards you don't know. You don't know whether the card is stolen, you don't know if for whatever reason the payment gets reversed, you can face ugly surprises. With bitcoin everything is clear. It offers more control.