It is about quality over quantity.
I judge applications for a local scholarship. It is a crystal clear difference between someone who is “throwing in the kitchen sink” and someone who demonstrates thoughtful, deliberate, and careful use of their time towards more focused goals.
I have heard of several high performing students applying to highly selective colleges who deliberately do not list all their ECs. They participate in an activity or three, superficially and strictly for personal enjoyment, but they know, for whatever reason, it doesn’t add to the picture they want to paint (that is the latter example above). Therefore, it won’t help their application.
Honestly, I wonder if the app has ten spaces precicely so AO’s can tell who is “throwing in the kitchen sink”.