two use-cases for #WebComponents that i don't see being talked about enough:
1. micro-micro-frontends using custom elements: you can have different people build different parts of the same page (even using different frameworks), and bring them together using custom elements.
2. stateful diffing using shadow dom: you can swap out HTML of a shadow-tree without losing dom state (e.g. focus or text selection) of slotted elements.
