Sadly, Sensei can't grab Pathfinder vows.
Though they can grab 3.5 Vows!
Therefor, I support this whole-heartedly.
Also, I'm kinda sad that the 6th level feature only allows you to use class features on other people: otherwise, there would be some fun to be had with stuff like Ki Stand ("Get up! Sifu says you are being lazy!") or...
Wait a second, it just says "when spending points from his ki pool to activate a class ability"... Excuse me while I check the Ninja. Because the 12th level upgrade for the 6th level class feature applies that class feature to everyone within 30'...
EDIT: A 2-level dip in Ninja (or gestalt Ninja) can grab you Forgotten Trick, which allows you to grant yourself a single Ninja Trick for [Ninja level] rounds. In other words, grant an ally within 30' a single Ninja Trick for 2+ rounds. Which can give cool stuff like Mirror Image.
A Monk 12/Ninja X with Forgotten Trick can essentially "cast" Mirror Image on the entire party for 3 ki.