I am not sure if we are not mixing up things together.
It seems that you talk about ability of Affinity programs to be programmable/automatable from outside with applescript or things like automator. This is very different thing. But this type of programmable user actions is on OS level and you can already do it.
If you put this in OSX Script Editor
tell application "Affinity Publisher Beta"
It will work and you can script user actions in the software.
I guess adobe is exposing more controls to OS so more things can be automated this way (and they have it documented here https://www.adobe.com/content/dam/acom/en/devnet/photoshop/scripting/Photoshop-CS6-AppleScript-Ref.pdf ) so you might want to want for Affinity to think about this. Who knows maybe it is easy for them to expose more functionality this way. There is probably some work needed to be done so script editor get documentation like some other software (screenshot of Adobe Illustrator) currently it doesnt.
But overall i think people in this thread are mainly interested fairly low level scripting access to Affinity products.
Personally i never found much that much usecase for automation of GUI apps on OS level. On the other hand what i totally need for my work is to generate PDFs. Imagine for example you are making book of all pantone colors from excel table - this would be insane without automation (and yes you can generate those pdfs somewhere else but ability to still edit afterwards is priceless).
I am doing both print design and also programming websites. And i have generated some books using indesign scripting.
Apple script is really bad choice for multiple reasons:
It is not platform agnostic - i am mac user but there are many win users and you just need shared ecosystem of scripts period.
This would mean having Serif supporting multiple languages one on mac one on windows. Too big burden.
As far as i know apple script is going away. It might just happen that apple just kills it.
Anyway Serif please do it some day. And please do just One proper way.