Has anyone tried this before?
Basically, you ignore any Jobs you get and finish the whole game with only the Bare Job.
I'm doing this challenge right now and it was much more fun than I expected, it requires completely different tactics and you have to bring a lot of Potions and Phoenix Downs with you at all times, and normally need to have one or two healers during boss battles.
One thing I like about this challenge is that, although the Job System is certainly enjoyable, it also tends to lead to decision anxiety and be a little stressful since it's occasionally so hard to decide on parties.
In this challenge you don't need to deal with that, you just grab whatever best items you can find and move on, and the simplicity of the whole nature of the challenge is quite pleasant.