As an iOS user and dev, I’ve been reading these comments confusedly.
Apple has exposed Siri to us as developers in several ways, one of which is called “Siri intents.”
The long and short of it is that app developers can hook into the Siri system so users can use Siri commands to control certain parts of third-party apps.
This means that users aren’t locked into using, say, Apple’s own Reminders app, and they can tell Siri to add things to third-party to-do list apps.
Users also have the option to create their own workflow via Shortcuts and give it a command phrase that Siri then responds to.
I assumed something similar was available on Android, but the responses indicate that this might not be the case.