I didn't suggest it did. It does mean "block that could be reused somewhere" though. Devs should consider that carefully when they're making components. If your block can't be lifted and reused because it relies on the parent structure or it expects something global that's not passed in as a param/prop/whatever then you need to think some more, because you're making something that's not reusable.

One day, someone, somewhere will want to use your component in a way that you didn't plan for. If you've created a hard link to a particular part of your app such as an expectation that the parent HTML structure will look a specific way, then you've made their job harder when you didn't have to.