A concern with Siri is it sends your voice data to a server to parse. When Siri is disabled, what data is collected via third party apps? I would imagine any time you use voice as a command in an app the iPhone send the data to a server to parse, even in third party apps. Is that the concern, or is it other data?
"Siri" is not just the voice assistant, Apple also uses that designation for other "intelligent" features, like "Siri Suggestions" [0]. The related personal information is shared across devices via Apple servers. Apple states that any analytics shared with Apple are anonymized [1], but users may still prefer to not share analytics in the first place. However, that can't be opted out globally, it can only be disabled per app [0]. Except maybe by turning off Siri in iCloud [2]? It's not clear. That's the criticism, it's difficult for users to understand what settings are enabling or disabling what exactly. It's quite complicated overall, and difficult to tell what you are and aren't sharing.
