I think that the additional information section can be used to expand on a significant EC that perhaps was not long enough in duration that it should be worked into the overall narrative presented in the other essays (either in the common app or in school-specific supplements).
For instance, my HS class of 2021 kid used the section to expand on an EC/business venture to which they devoted tons on time at the end of junior year/summer/beginning of senior year. It was directly related to the pandemic.
Nevertheless, I do agree with the OP’s general point that less can be more.