The Favourites view is essentially a pared-down version of the Following feed that shows only the accounts you’ve added to your favourites list.  This makes it easier to catch up on the content you consider most important, like posts from your best friends and favourite celebrities, in chronological order without having to scroll through posts from every account you follow.  You can add up to 50 accounts to your favourites list by tapping the Following button on their page and choosing Add To Favourites.