Facebook Coin: What's the realistic angle?

It's that time of year, the post-earnings lull where equity analysts take time to digest new company information and either reaffirm their views or offer material changes to their theses. For some looking to make a splash, the occasional brow-raising bold calls trickle out as well.

This week, Barclays' internet analyst Ross Sandler released a note to clients which walked through his bullish view on Facebook Coin, suggesting the project could unlock as much as $19 billion in incremental revenue by 2021, and a conservative base-case forecast of $3 billion. That's not a typo.