Both are reasonable, though I understand why Google is pushing back against it.

The assistant angle simply is saying that they have to expose APIs that they are already using and that they can’t lock away those features, especially on an open-source operating system.

On the second point, it’s just mitigating the first-mover advantage — just because Google existed before something else, potentially before an inventor-of-a-competitor was even born, doesn’t mean that they should be immune to competitive pressure.