In the past, Apple has already ported several successful mobile apps to macOS, and the Coopertinos do not plan to stop. What’s more, Messages and Siri Commands may appear on Apple’s desktop platform in the near future. A hint of this was found by the famous developer Steve Troughton-Smith.
According to the available data, the Messages app will be much like its mobile version. This applies to both functionality and interface logic. The utility will support sending different messages (text messages, messages with effects, audio messages) and sending files.
As for the Mac version of Siri Commands, there is no accurate information about the functionality of this utility yet. However, Troughton-Smith believes the app will be much inferior to Automator in terms of available actions.
At the moment it is not known when Apple plans to add two new standard apps to macOS. It is possible that the utilities will be available with one of the major macOS Catalina updates.