None of the above.
When you take a snap (a photo or a short video) there are a series of filters you can apply to it. A few are instagram style colour filters but there are others that include the temperature, the time and your speed.
Additionally, there are a whole load of geofilters that...
It may be, but my use case is different. Those I communicate with via messaging are done via iMessage (with the occasional Android freak reverting to SMS) or Facebook Messenger.
I have no real need for another platform to use for messaging, even given Snapchat's funky filters and face lenses...
Any keen Snapchatters on NSC?
I've had it on my phone for ages, but never really got round to using it, largely because the UI is so confusing that I didn't really understand how to use the bloody thing. (How Snapchat Built A Business By Confusing Olds)
However, with the investment of a little...