Once you know the Snap UI it works very well. Kind of like a DSLR camera, it takes forever to learn all those buttons and functions and become habitual with them, but once you know how to find all the functions and operate the camera properly it's apparent that everything has been beautifully placed and carefully thought about. An easy to learn UI isn't necessarily the most efficient or versatile to use.

Old people wonder 'WTF is this Snapchat?', they download the app, dick around with it for a few minutes and dismiss it as incomprehensible. It's a feature, not a bug.