Snapchat didn’t start like this. Of course, in time they adopted this technique. But they already had their evangelists army who adopted the new interaction gradually.
When Snapchat was big enough for most us to give some attention it already eliminated most of its UI elements and got the ‘hard to use’ reputation. I usually get as a reply, ‘It’s meant to be hard to use so their parents will stay away from it. A private space for teenagers.’
I usually make more taps than I should when I’m using Snapchat. It doesn’t even get my face if there’s a shadow on my face. I saw other people struggling to get the filters too. But they don’t say anything. You are old or not cool if you say it out loud you don’t know how to use it.
So basically, the evangelists brag themselves to their friends. They learn without asking for it and then they feel special and brag in front of others.
Shareable design a better approach? If we use the app on a daily basis, yes, I believe so. If the app is only for specific cases keep the UI updated on the latest trends, keep the icons and make it easy to use on the first try, I won’t invest time in every small app.