By default, we ask Shopify for a list of all products that are featured in your store catalog and create this category in the app if any featured products exist. Shopify will mark all products as featured if they are not assigned to any collection.
If you do not have a specific reason for having a product with no collection, then we recommend you create a collection you can place all these products in and then hide the collection. This will remove the "Featured Products" category from your app.
Of course, if you are good with the "Featured Products" category then do nothing.