Phantom Dancer gives you a little over 50% effective damage per auto on all targets if you already have infinity edge due to the additional crit and the multiplier you already have from IE, plus it gives 50% attack speed instead of 40%.
BotRK passive with 8% current health against an ideal target (Cinderhulk + Spirit Visage ~2300 hp at level 11) only deals 186 damage on a max hp auto (reduced by armor because the passive is physical).
Phantom dancer also costs less and has a better build path. I really really don't think the BotRK active alone is enough to overcome that. So no, I disagree entirely with your opinion.