The NHS at DD’s high school requires members to tutor at the school’s resource center in addition to their community service. So evidently there are a large number of high-performing students who don’t bother to join, even though they’re eligible. For them it comes down to a time-management choice.
Think of it this way: 50,000+ high schools with tens (or even hundreds) of members each… it isn’t that selective. For the exceptional applicant, the NHS on a college application is bound to be ranked quite low among their list of ECs/awards, if it even makes the cut at all. Not that s/he doesn’t share the very worthy values of the NHS but because s/he will have demonstrated them (and other values the college is looking for) in other, more meaningful-to-him/her ways.
I disagree that “it means nothing”. NHS looks for scholarship, service, character, and leadership. Those happen to be four of colleges’ desired traits among their applicants. However, I absolutely agree that NHS is hardly the only way for an applicant to demonstrate those traits on a college application.
The special tassle, cords, and pin (for the schools that partake in those) do look fantastic on a graduation gown, if only for the two hours that may matter.