Does anyone have this update yet? Is it U.S. only for now?
Iām confused that all news outlets state this in the present tense and even put the word ānowā in the title, while for me the latest available update to the ST app (1.7.39) was published a week ago and does not contain the feature.
In the app, go to the Routines section and tap on the 3 dots. There should be the option to run a routine with siri. That is what shows up for me.
It does indeed show up there, thanks!
I was looking directly in the Shortcuts app, where SmartThings is not listed.
Once you select which manually run routine to use with Siri, it will appear in the shortcuts app. 
Thank you for pointing that out! I had read the news on the integration but completely overlooked that!
Cool - now all ST scenes as Shortcuts on the iPhone locally and/or in Homekit automations.
The one significant downside of this implementation I noticed is that apparently, when executed from the iPhone (either manually or in an automation in the Shortcuts app), it always has to open the SmartThings app for the scene to be activated. That also means that any automation that runs while the phone is locked will fail. I wish the shortcuts could simply run and activate the chosen scene in the background, without opening the app.
Did any of you try if it is possible to run them from a HomePod or as an automation in the Home app?
I have not had the time to explore yet.