It's discovery/referral gating. Teens who get Snapchat upon hearing it from a friend can ask their friends on how to use it, and it stimulates conversation and feature discovery. If you don't have at least one existing friend who is experienced at using Snapchat, you're probably not in their target market (by design).

You see this social gatekeeping in how they distributed their spectacles, too.

There's no good way, and I really dislike this modern trend of un-discoverable UIs.

Slack's iOS app has like two side-swiping menus essentially stacked on top of each other. One of those menus (the first one) is NEVER what I want. The whole thing is so confusing, and I have to relearn it every time I actually need it.

>https://www.google.com/#q=snapchat+swipe+left

Just consult the nearest "X things you need to know/didn't know about Snapchat" article /s

Because you try it once or twice when exploring a new touch interface?

It takes all of < 1 second. I get it is obfuscated but we aren't talking about a crazy level of interface hiding.

People expect to be able to swipe on most interfaces these days.

It does take < 1 second. And then so does swiping right. And left. And up. And pressing. And long-pressing. And double-tapping. And two-finger tapping. And two-finger swiping (in all directions). For every element on the screen. For all screens.

See you in a few hours.