It certainly has a number of health benefits - if only on mental health at first, then certainly on your physical health later (for they are both intrinsically linked). In the sense that it allows each person to precisely divide their personal life and work commitments in a way that is personal to them, bullet journalling cannot help but do good to whoever seeks to use it. However, I would suggest that it should not be used as the sole medication for your problems, but rather as a method through which you can have more time to work on yourself.