#2 by hanako - Jun 22 2012
There are checks made on every skill at *some* point. How useful they are varies.
Ciphering is not the most useful skill. It comes up with the letter from Briony, and deducing the identity of an assassin if you trigger the early-game assassination attempt. That's about it.
Meditation comes up several times, but often it serves as an option in case you don't have composure (at times when staying calm is important). Very high meditation also unlocks an important piece of information for one of the subplots. It's more useful than ciphering, but it's not usually critical.
World History is mostly a background information skill. The only time it's ever checked in-game is in relation to the end-game events with Shanjia. You can get an extra option from it on one plotline, but the option isn't particularly important.