
Unless they telling who screenshotting ya shyt, showing
every single person who viewed your story and making sure that
only you can see who you follow on the app - like snapchat then SC doesn't have to worry about going out like Vine.
IG makes to where someone who doesn't follow you or who doesn't even have an account or the app, can peep your moves (even if your shyt is on 'private', people can still see your bio, how many people you follow, how many followers you have and search engines index your account so people could trace your acc history/info if they cared enough) where as SC gives you more control over eliminating prying eyes from even seeing anything if they try to look you up or keep tabs on you.
Snapchat is fundamentally more lowkey, personal, brief and designed to be less of popularity contest/competition than social media platforms like Twitter and IG.