Improvement in anything is improvement in everything
By learning any new skill, you improve all other skills, some clearly, some microscopically. For example, becoming a better public speaker clearly makes you a better employee, probably a better writer and a better spouse. But it also helps in completely unrelated matters, literally any skill you can think of.
Why? Because the mechanism through which you improve is always the same, and that transfers. The discipline, the attention to detail, the continual noticing of something to do better next time… This, combined with an ever-increasing confidence in your ability to just do things you set out to do, leads to all-around improvement.
Common knowledge is to believe someone who is very skilled at one thing is more likely to suck at other things (because they spend all their time on their strong area?). While there are many such cases, it’s surprisingly often true to assume that if a person is more skilled than average on one thing, they are also more skilled than average at an unrelated thing.
Some parents believe their children are better off improving in a socially valued skill, like the piano or mathematics. I believe it doesn’t matter much what they do, as long as they develop mastery in it. (And probably the best path they can develop mastery in is whatever they choose themselves, not what I choose for them.)
I believe if you’re really good at anything that requires skill, there’s no reason why you couldn’t be really good at another thing, if you pursue it with intention. An interesting candidate is not one with all the right credentials, but one with a background of mastery, no matter what it is in.
By becoming better at cooking, I become a better employee. I become a better writer. I become a better human.