If anything, I'd say it's a smart solution in certain set-up's where one wants to route the signals separately for whatever reason. Let's say you have a receiver that can't handle 3D or 4K picture signals - you can then route audio from one HDMI output to the receiver and the other HDMI output for the video directly to the display without involving the receiver.
But in terms of pure performance, splitting signals won't make any difference. Some Blu-ray manufacturers like to claim this is the case but that is pure marketing gibberish. As mentioned above it's good for other reasons.