Just because you use galuf as a monk so often that you think those are his real clothes, doesn't mean that bare=monk 

  (I do that.  I restarted the game and saw galuf's real clothing and was like "wtp, when did he dress like this?"  then when I got back to the monk job class and slid him in it I understood)
But yes, if you're bare, suppin, don't have any job class you're dressed up in, y ou get to choose two abilities. 
And people do choose this once they master all the others because of the reasons mentioned before.
I beat the game the first time with mimic:]  mimicking the bahamut summon= <3