It is supposed to be for people 18 and up, but as with Tinder, there is no age verification. News and Media Literacy. For most of these apps there is no good reason to have them.
I think this idea is open to abuse because anybody could find your snapchat or kik username. If you search for "hide apps" or "hide photos" in either of the app stores, you can scroll through and at least get a sense of what to look for.
Of course, that could change, so I would put this in the "watch carefully" bucket.