Ely, I do understand your hesitation and concern that if it isn’t Snapchat today then it’s some new shiny object tomorrow.
“My” humble explanation why Snapchat or any other emerging popular social channel is relevant comes down to the idea that to properly deliver a core message or stream of thought in social you have to think hard about the experience mix of channels and what type of short term influence or long term lasting impression (or both) that you want to leave the reader.
As in your example, you are following thought leaders that exist on other social channels and now you started following them on Snapchat, probably centered around very connected content. In that case, maybe their professional opinions are established on LinkedIn or a blog…but to reinforce it or introduce different ways to test an opinion they use Snapchat. I liken it to a social channel that retains content is that required textbook that is foundational reading and a social channel like Snapchat with a limited content lifespan is a type of flashcard to imprint visually a concept but does not need to last long to deliver the intended effect.