It's a good question. In a sense, the cube is caching, just materialized ahead of time instead of memoized on demand. A result cache still needs a live database behind it for misses; the cube has no misses, since every question the dashboard is designed to answer has data in the cube already. And for this experiment, the goal was to forgo a database to serve the data in the first place.

I provide caveats for when this would work vs. when it doesn't in the post. For a lot of customer-facing dashboards, I think it's probably pretty good.