Drupal thrives on community contributions in the form of patches and documentation to both contributed modules and core. This helps the project move forward and stay relevant.
Not everyone who works on open source projects is a senior developer. Smaller tasks help people increase confidence and gain experience, which, in turn, leads to more contributions. Code is very important, but so are all the other parts. Contributing back to Drupal helps folks to become better developers. A more polished Drupal leads to a better overall experience.
But how does one become a contributor?
There will be a lightning round demonstrating the process of finding an issue to work on, creating an issue, spinning up a Drupal instance, and digging into the issue queue.