I only tried to kill someone through a plot once and nothing happened so I'm not sure, but I think it also triggers an event if your plot power is high enough. I guess it can eventually be safer and/or cheaper than a simple assassination.
If you think you are good at something, there's an Asian on YouTube better than you.
you get an event to kill them based on their rank the mean time is based on your plot power, Success is random chance based on various traits that raise or lower the chance, a plot assassination can take up to years to succeed. Your best bet is once you *see and oppurtunity* save your game the attempt will be made soon after if it fails reload and try again. And plot power over 150% seems to be useless.
"I am the punishment of God...If you had not committed great sins, God would not have sent a punishment like me upon you. - Genghis Khan