You're right. I misunderstood Op's "Even if you get down to 0ms" to be referring to network latency, stating that encoding and decoding would still be a problem (which the Wii U shows it's not).

That said, 15ms network latency isn't too bad at all, considering that it takes your TV 40-80ms to display a frame through HDMI. Fortunately, with the advent of VR display manufactures finally took notice of this built-in lag. So that's getting better, too.