You gotta find what works for you. People build differently based off of what they're comfortable with. There's no such thing as a "best build." There are multiple optimal builds with different build paths. No one build is going to work perfectly for every person playing that champion. I was simply stating that I feel as if Bork is an optimal rush for me and that people should give it a try as well to see if they like it.
Also, another thing to consider, is how passive the early game tends to be for the ADC's in LCS. They're not making crazy duo kills with their support early. They're just farming up for big items like IE or BT. On the contrary, in a lower ELO in solo queue, you're gonna be looking for duo and solo kills a lot in lane, so a bit-by-bit build path to bork guarantees you're getting stronger with each back considering all items that build into bork are rather cheap. In the C9 vs. CLG game, you'll notice Sneaky had 0 kill participation until after BT was finished. TL vs. NME showed Piglet with a really nice early game, but he picked up a lot of these kills with only a Vamp Scepter and Greaves. This build could have easily gone into Bork considering Vamp goes into BT and Bork, so either way, the pieces of Bork still can do you well.