Chapter 7 GroceryTile key redundant?

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1

grocery_list_screen.dart

Dismissable has the key:

return Dismissible(
            key: Key(item.id),

And InkWell is the child of that Dismissible widget whose child is a GroceryTile:

            child: InkWell(
              child: GroceryTile(
                key: Key(item.id),

The key parameter seems to be redundant for the stateless GroceryTile widget here.
If you delete it from the code, the app still seems to work perfectly (adding/editing/deleting items seem to work well).

Please advise,
Márton