Do extracurricular activities matter for a person in academia? The only thing I can think of is scholarship application. But how much do scholarship committees look at extracurricular activities? Do they look for the positions that you held?

Frankly I'm very weak at extracurricular activities and don't know what to do.
I think this would depend on your meaning of "extracurricular".  In terms of having photography as a hobby, I am not sure how that would help.  However, for faculty, extracurricular activities that benefit the university have been well discussed on academia SE, for example, serving as a reviewer on a journal.  Other activities that could be seen as beneficial is volunteering for a first robotics at the local school (if the university if public, that may be more important for secondary education), or organizing a TEDx event.

In general, I would view the reason anyone would care about extracurricular activities is for students; how does it make the student more diverse, more capable, more knowledgable, easier to work with, etc.  And for faculty; how does it make the faculty represent the university better, improve student or research connections, make their own research more interesting, etc.