So let’s say the company wants to save the cart, the user’s favorites, and their search preferences so when they come back it’s still there. A cookie isn’t a database. So they store that info in a DB using the cookie id as the index. Is that a phantom account? You’ve got rows in a DB for a user who never signed up.

Generally when you want to save favorites, most, as far as I've used, storefronts require that you create an account before allowing those functions.

You can book a hotel room as a guest on many hotel sites