Perhaps the most important use of courage is in self improvement.
So much "self-improvement" these days is like someone idealizing the pose for their bicep curl to get fit. They hope that with preparation, the form will allow them access to a moment of inspiration, and they will be fit. Like a revelation from perfecting their archetypal example, it will happen in a flash. And the path forward will be illuminated. It is a coward's farce.
All feedback is useless if you don't have the courage to face the truth undaunted. Self improvement requires change, admitting weakness and a sincere desire – and in that state, developing a plan you can follow relentlessly until it's addressed. That demands continual courage. Without that virtue, you will likely never develop the others to be as strong as they should be.
It goes without saying that because facing your own flaws is quite scary, we shouldn't scare people who don't explicitly consent to this. It wouldn't do any good, anyway – but it's also impolite.