Before Snapchat Stories was copied by Instagram, the social network didn’t have auto-advance nor did they clutter your friends Snapchat Stories with their Discover channels. Snapchat is now pulling the auto-advance feature because some users were confused by who’s stories they were viewing.
They’ll also be moving down the Discover channels to promote your friends stories. They’ll also let you create a playlist where you can group together with friends or brands where you’ll still have auto-advance within that circle of friends.
Snapchat is making this change for a better user experience, but also because users aren’t as active on the Discover channels as they are when they’re viewing their friend’s stories. They also don’t have to worry about ad money as they’re displaying ads between stories. Making it possible for them to make money even if you’re not going to the Discover tab.