it seems likely it's both a better model to some unknown extent and doing this "we have to give it to the defenders first" thing is super great marketing material. it seems an entirely natural marketing campaign "announce that we can't even give the model to everyone at first, it's so great!", plus there's some truth to it, even better.

unless you are an employee at anthropic and shouldn't be talking about any of this at all, there's no way to know what the model's capabilities are.