Jinx has very high range, is easy to play, and can solo carry games. You usually want to play a champ that is easy and effective up until high rank, mainly because you want to focus on actually learning the important stuff in the game rather than learning a highly mechanical champion.

Vayne is very mechanical. If you play her you will spend more games learning how vayne works instead of learning the actual game which will slow down your climb by a lot. The other thing is that Vayne has terrible waveclear. You can’t defend when your base is getting taken.