It wouldn't be good for your business if you exclusively accept bitcoins. You can't exclude fiat yet because most people still transact in fiat, and most things you buy are still in fiat.
I agree. I think a better idea for the OP would be to accept bitcoin via coinbase and offer, say a 4% discount for customers who pay in bitcoin. I would estimate this to be the lower bound of the effective cost of accepting credit cards (after accounting for fraud and charge backs). This would result in the merchant having the same profit on a per sale basis, however would potentially be able to gain market share due to the permanent discount.