I'm inclined to believe that rationality is more an instrument rather than a goal, as you try to describe it. Being attached to material trinkets, (or not) will be a rational choice for the one who developed his rationality and was able to think his choice through, while irrationally dismissing the utility of mundane gadgetry as well as wholeheartedly embracing it, most likely as a result of an induced bias, exposes the undertaker to unconsidered, not-yet-evaluated risks - hence the label "irrationally".

There is some seed of truth in what you're saying - the balance between the effort of developing a rational art and the likely impact of that development on one's goal has to receive the necessary attention.

To go with the example provided (the body-builder [the rationalist jedi]) - going straight towards his final goal (obtaining an Adonis physique [being a rational jedi]) will help him develop more muscle mass [more powerful rational skills] which would mean more fat-burning cells in his body [more chances to make the right decisions when various day-to-day challenges arise] to deal with the extra 200 pounds [whatever skewed perception or behavioural pattern one has], which, in my opinion is more close to optimal than a simple diet [blunt choice of "what is right" based on commonly-accepted opinion].