I think it’s more efficient to test a bunch of fixes together instead of as and when needed as Asobo are often making sweeping changes which need regression testing to ensure systems talk to each other correctly.
Patches are included in the core application update I.e. the 10 GB download, yes it probably does include some AI related content like the architype changes for the USA building sets but on the whole it’s an application update.
The content comes later and is delivered through the Marketplace I.e. the 4 GB USA World update and you can absolutely play the game while that’s downloading.