I think Snap is pretty dead. Between Instagram and Facebook stories, I just don't see the appeal of Snapchat. Most of the time, if I want to send stupid shit to my friends, I do it in Messenger because we can laugh about it later, too.
It’s more likely you’re missing something and they do have a user demographic that is strongly entrenched. Of the users they do have they have strong user activity.
Take my 11 year old sister. She primarily uses snapchat and I can’t see her ever switching. She definitely doesn’t shop around these apps based off of some pro/con table of features.