Which only helps if you're trying to prevent them from collecting the data rather than use it for a given thing, which is the thing they're not doing.
As an obvious example, if they keep all your files/messages on their cloud storage by default, they have all your files/messages by default.
> and you can - as a government - actually just go to their servers and check what they are doing (with necessary permits and lawful action)
Which generally only happens when you have reason to suspect they're doing something, which is the thing you wouldn't have when they're the only ones who know that they're doing it.
And even if you do go to look at the servers they have in your jurisdiction, there is no way to tell that the data hasn't been copied to servers outside of your jurisdiction, or what is happening to it over there.