[thom]

The magic here isn't that it's giving you streaming updates of a database, it's that it's making some of those updates ridiculously fast. The point is that if you have a materialized view that takes a long time to update (or just a stack of views that are slow to return results), you now have results instantly whenever changes come in. If you built a bunch of code to work around this and do clever invalidation of cached data, you get to throw all that away. The input/output into the system is less of an issue overall.