Links give extreme flexibility to bring almost anything into the app. A Link can point at a SnapPages page, an external URL, a phone number, an email address, an in app Media item, a Calendar, a form, a giving page, or a specific List. When something belongs in the app but is not native content, a Link is how you get it there.
Leveraging SnapPages makes the app experience feel native. Because SnapPages is the same platform as the app, pages served from it inside a Link look and behave like part of the app instead of like a foreign website. Use SnapPages pages for anything that needs richer layout than a Media item or a Link card can carry: staff directories, ministry landing pages, first time visitor guides.
Watch for what I call completed transitions. When a Link opens something that finishes with a Back button or a Done state, the member returns cleanly to where they were. When a Link opens an external site with no clear way back into the app, you have lost them. Always test the return path, especially on iOS.
Rule of thumb: open in app whenever you can. Open externally only when the destination actually needs a full browser, like a third party form that will not render inside the app view. Every external hop is a chance for a member to close the app and never come back.