I am thinking of unlocking the perk to reverse pickpocket poisons on a passive target

How efficient is poisoning for an assassin ? Is it only interesting for role-play ? How does it work on master difficulty (for example can we reverse pickpocket several poisons in order to kill the target in one shot ?)

Is the perk worth it ? I would be thankful for your enlightenment

It is a fun and original way to play around with enemies. I wouldn't say using damage poisons are the best to use, though; you're better off paralyzing or slowing your opponent, giving you the edge in a face-to-face battle. You can also make NPCs attack each other by planting a few Fury potions.

The problem with all these is that, most of the time, you can just slit your enemy's throat in these situations. So, poisons are situational, but a lot of fun to use and pretty neat from a roleplaying perspective.