This is such a great way to find out just how much can be done for you.

I used to do competitive programming competitions (similar to HackerRank challenges) and learning the standard library was a huge driver to finding the best solution without reinventing the wheel.

But even in the day job, knowing what to use without pulling in a new dependency can make a big difference.

This can go a little further to learning common packages that your ecosystem uses, and how best to tackle problems with them.