I just installed the public beta on my 8+. I don’t have a developer account but decided anyway to search around the settings for Siri.
It looks like we can assign Siri shortcuts to some workflows we have already set up in the WorkFlow app.
Go to: Settings > Siri & Search > More Shortcuts
Scroll to the bottom and the Workflow app is listed with a selection of my workflows.
If I clock on the +, I can assign a siri phrase to trigger the shortcut.
I thought this was only available to Developers with the new ShortCuts app.
Stephen