Open Source thrives on community contributions in the form of event organization, marketing, communications, volunteering, and yes, even code. This helps the projects move forward and stay relevant.
Not everyone who works on open source projects is a coder or 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 Open Source helps folks to feel connected with their community. A more polished project leads to a better overall experience.