I agree that this is not general AI. I think we could be looking at the future of query engines feeding probabilistic compute engines.
But there's a lot of places where a lack of concept of "truth" is no problem, like as you say, query engines. Query engines aren't about truth; they're about matching, and that is something this tech can conceivably do.
In fact I think that would be a more productive line in general. This tech is being kind of pigeonholed into "provide it some text and watch it extend it" but it is also very easy to fire it at existing text and do some very interesting analyses based on it. If I were given this tech and a mandate to "do something" with it, this is the direction I would go with it, rather than trying to bash the completion aspect into something useful. There's some very deep abilities to do things like "show me things in my database that directly agree/disagree/support/contradict this statement", based on plain English rather than expensive and essentially-impossible-anyhow semantic labeling. That's something I've never seen a query engine do before. Putting in keywords and all the variants on that idea are certainly powerful, but this could be next level beyond that. (At the cost of great computation power, but hey, one step at a time!) But it takes more understanding of how the tech works to pull something interesting off like this than what it takes to play with it.
Probably a good blog post here about how the promise of AI is already getting blocked by the complexity of AI meaning that few people use it even seem to superficially understand what it's doing, and how this is going to get worse and worse as the tech continues to get more complicated, but it's not really one I could write. Not enough personal experience.