The obligations and motivations are really there as hooks to use, abuse or ignore as you see fit in FFG Star Wars.  They can be handy if the story is in a lull and you need something to happen.  They can be used as ties to encourage a reaction out of a character.  But most of the time they are just there and out of the way.  They are probably the weakest part of the system and fortunately they are the least important.