Well, if you want to know the total economic loss due to weather, you might also want to e.g. include $900 million events.

If you want to know whether there is more disastrous weather in general, you probably don't want to completely ignore the vast majority of land. (Where destruction amounting to $1 billion is fairly unlikely)

For almost all interesting questions around changing trends in catastrophic weather's effect on the economy, I'd want a different measurement. What would you think, you could use this for?