It Is relevant because regardless of if the 780 will be the target, when we are talking high end graphics cards, the single fastest product will always be the benchmark, especially if the target is surpassed which seems to be the case here.
To the "market" the Titan is a cut down quadro, but acceptably so as it was the single fastest card. The gtx 780 is viewed as a "cut down Titan" because it is, acceptably so because it offers near Titan performance for a more affordable price, but the Titan is still king, and any contenders will have to measure up to the king.