Usually you are invited to join those honor societies...and if you were invited to both you could join both.
To be inducted into NHS, in general you need the four pillars: Scholarship, Service, Leadership and Character.
Guess what colleges/Service Academies are looking for? Scholarship, Service, Leadership and Character.
So NHS is a way of the school honoring the students who excel in those four pillars. That is a very good thing! We honor football players and band members and such...let's also honor academics!
Also, parents love to see their children publicly honored.
So if the question is:
1) I don't want to bother to apply - don't worry, colleges care about what would get you into NHS, not necessarily the title. But your parents sure would be proud.
2) I did not get in. don't worry, colleges care about what would get you into NHS, not necessarily the title.
So make sure you find ways to exhibit Scholarship, Service, Leadership and Character even if you don't have the "title" of NHS.