I beg to differ. People that develop a grit are the ones telling those that didn't what to do. If they couldn't get the work done, how else do you expect them to lead? You can't define a submissive person as simply as above. A submissive person is also one that didn't have the grit to develop his communication skills, his people skills, his critical thinking skills, and his creativity, etc.
Surviving prison develops grit. Therefore it is beneficial to go to prison.
Counting the grains of sand on the beach develops grit. Therefore, it is beneficial to count the grains of sand on a beach.
Point: not all activities that develop grit are beneficial. The implication of the grit argument is that any tedious activity has some benefit - if not for anything else, then at least for the development of 'grit' itself. Which is a ridiculous argument; some tedious activities are tedious because they are pointless. A better lesson to learn is to spend your time wisely - on activities that are tedious for a reason.