[Matt R.]

What happens when your opponent starts to read you and knows when you're bluffing him off his 'weak' (but better) hand every time and starts to call? You can't force your opponent to fold their marginal or drawing hands every time. You're still going to have to have the best hand by the river sometimes -- and if you choose to know the final board, you will know this with certainty sometimes, and the times you DON'T you will still have a very good idea.