It's disappointing that the article doesn't lead with this limitation. We (and everybody who's used Snapchat) know that self-deleting messages aren't truly possible, but there's no reason everybody should.
This is definitely a useful feature to manage sensitive documents within organisations where good faith (but not necessarily diligent policy adherence) can be assumed, but it's pitched dangerously wrong as you say.
This is definitely a useful feature to manage sensitive documents within organisations where good faith (but not necessarily diligent policy adherence) can be assumed, but it's pitched dangerously wrong as you say.