ECs that students do because they are passionate about them are what they are. I wish we didn’t have a world where students/parents/schools didn’t create ECs to look good to colleges or didn’t invest extra time and energy to achieve in those realms (if the intent is to get into colleges. But, that is our world.
For the purposes of getting into colleges, ECs are useful to the extent that they a) show extraordinary talent/dedication; b) are memorably interesting; or c) show unusual passions (this may be similar to b).
My son didn’t try to get into college via ECs but did have a memorable different set including designing complex board games, competing in Moot Court competitions, and co-authoring a young adult coming of age novel (a publisher was interested but his adult co-author somehow got the author’s equivalent of stagefright and it is dormant). When my son went to orientation at a pretty top-tier LAC, the director of admissions greeted all of the students and used several examples to describe how interesting the class was (mentioning only the ECs but not names). My son was one of the examples.