This item is not a BAD item for ADC. There are "BETTER" options, but this one provides survivability, attack speed, MAGIC DAMAGE, and easier farm clear.

Then again, you know the Meta always wins championships. Oh wait...

Infinity Edge, Bloodthirster, Last Whisper, Phantom Dancer, Trinity Force, Beserker's Greaves.
There just aren't any other offensive items on ADCs that are playable right now. There's a reason that Riot is completely revamping the item system: the current system is stale, and there are options there that are just better than other items. Over the course of a year, smart people have crunched the numbers and found that for champions whose only goal is to output the highest DPS possible in the late game, AttackSpeed/AD/Crit/ArPen all multiply together to create the best build.