Red smite ADC

Vayne with Sated Devourer is really strong because of its passive and adding the red smite makes it even stronger, being a really strong power spike when she gets thirty stacks

The true damage can be nice but I wouldn't count on the 20% damage reduction from whoever you hit to save you, in most cases you're better off with heal, for a multitude of reasons.

Also to turn it into challenging smite takes you building into an item, which takes gold and an item slot and currently the only reliable item I could think you would build would be warrior, which truth be told, I would think that 2250 gold and lack of a summoner for such a crucial part in the game would make 40 AD, 10 ArP and 10% CDR not even remotely worth it.

Don't do it. Since you have to take Smite to even use it, you're already planning on the fact that it'll succeed. Then your only choices are Warrior and Devourer. Warrior is less useful than other items for most ADCs, and Devourer will take forever to stack even if you can take advantage of it.

Vayne and Ezreal are the only one I can see doing it, but even then you're better off trying to take them into another lane than even trying to compete in bottom.

You're not that tanky to begin with, so it's kind of useless.