Great post, Craig. I'm also somewhat skeptical of Augur. Like you said, who wants to vote on the weather? Since it's a protocol, I can see other projects building on top of Augur to create specialized betting markets around sports, esports, business outcomes, politics, etc. You might want to look into futarchy, "a form of governance proposed by economist Robin Hanson, in which elected officials define measures of national wellbeing, and prediction markets are used to determine which policies will have the most positive effect." I doubt nation states are likely to adopt this, but can see decentralized organizations giving it a shot.
One final take is that Augur could be used to power a global digital casino based on traditional games (e.g., poker), derivatives of those (e.g., betting on who has the best hand), and increasingly complicated games incorporating an infinite number of other possible event outcomes.