Encapsulation might be overkill for a single developer, but it very much matters for teams and using third-party components. If you want to drop in a calendar

Encapsulation might be overkill for a single developer, but it very much matters for teams and using third-party components. If you want to drop in a calendar component into your page from npm, it helps if that component's styles don't leak into the page, and if page scripts don't accidentally mess with component internals.