Nice dodge, Netflix.
The companies most likely to do this are those that can't afford a proper distribution platform and/or are looking at any way to cut resource usage down on their end. One of many such examples is in the game world, especially on Steam, where companies install windows services or a launcher that torrents updates. Sometimes they continue to run when the game isn't active. So the developer saves money, and the consumer gets left with a slower internet connection.
Is Netflix doing it for this reason? It's very maybe-ish. They're being pretty evasive about the size of the database, and this could just be a trial balloon to see if anyone notices before flipping the switch on some darknet. That's usually how deployments like this go. Or, it could be just what they say -- a way to speed up performance. I'm skeptical because they're keeping a tight lip on how it will be implimented. Will the data stream be compressed? Delta updates daily for new content? How will the cache be synced? There's no technical errata, not even what platforms it is deploying to, which considering that this is a *technical* update, I'd expect more of. The lack of technical data suggests to me that management is in the loop -- and is hiding something.
What, is anyone's guess.