To promote a new grocery delivery service, you can talk about how fast it is, how easy to use it is, how convenient it is.
Or you can build a community around unique recipes, with ready-made ingredient packages available for purchase, a weekly menu-planner that takes allergies, calories, habits, and personal preferences into consideration, and some way for the users to contribute (pictures, comments, own recipes, etc.).
Of course, if you can leverage both, that’s fantastic.
But things like fast, easy, and convenient are easy to copy.