However, I think your description also fits CLI's which has always led me to wonder if maybe Snapchat's UI is really a way forward as a "native mobile" CLI of a sort.
We're already seeing things like pinch-to-zoom, swipe to move next, etc. being taken and recombined for all sorts of apps.
This is probably one of my favorite things about the CLI versus GUI. There is nothing worse than working with cli apps that have weird incantations.
I've been using command-line interfaces for a pretty long time now, and I'm incredibly thankful that these days I can look something up on the internet and generally find a list of some examples on how to use things. Man pages are generally incredibly verbose in all the wrong ways (far too much information, far too little that you actually want) and the -h switch at best gives you some flags and descriptions that are fundamentally too short to teach you anything useful. There is no real global standard for what kind of flags or inputs do what things (for example, far from every program with a CLI interface will actually accept "-" as an input file even though that's one of those things a lot of people use and should therefore be pretty obvious), further obfuscating the core workings of anything you might be using.
It is completely nonsensical how Snapchat works. You have to swipe every which way and there's no clues when to swipe where. You just have to memorize the magical incantation to do what you want through trial and error.
We as a society have built up a fantastic 'language' of UI. We know what buttons and menus, etc do. Snapchat throws away all the ways you want to intuitively navigate and give you no clues about what to do instead.