It's not pointless at all- it's the core idea behind Stoic philosophy aka "the dichotomy of control," and has proven very effective at improving people's mental health through modern therapy methods like CBT and ACT.
One can still do everything in their power to prepare for, and mitigate things outside their control, while still keeping in mind what is in your control and isn't so you don't become emotionally dependent on outcomes outside your control, which is ruinous for mental health.
Having empathy, and caring about doing the right thing actually work better when you stop obsessing over and wasting all of your energy on things you cannot control.