What you gain
A feature is one place to read, delete, or hand to someone. A change to notes stays inside features/notes/ except for the composition-root factory. Extracting the feature later is mostly a folder move.
The wire mapper sits next to the endpoint, so you do not grow a shared wire_mappers.dart hotspot just to save a note.
What it costs
Infra sits next to domain. Nothing in the folder tree stops note.dart from importing note_repository_impl.dart. The rule is the import, and you have to keep it.
Shared business rules slide into shared/ or get copied into the next feature. A workflow that saves a note and updates a notebook has no obvious home: it is not only features/notes and not only features/notebooks.
You cannot open one directory and see every repository or every use case. They are spread across feature folders.
Back to the introduction, or continue to when to use it.