I'm a big Echo fan, as I have about ten of them spread across the home and office.
However, whether I use Alexa, Siri, or some other voice assisted service to schedule an activity, I love how I can use Handheld Contact to pull them into Act!.
For example, yesterday I invited my mother and niece to breakfast on Sunday, and the workflow followed something like this:

1. Once everyone was onboard with the outing, I turned to my Echo device and said "Alexa, schedule breakfast at Denny's at 10AM Sunday", and within moments the event appeared on my calendar on my phone.
2. I then used HHC to import that new activity (Homescreen > Import/Export Calendar > Import Calendar)
3. Once the activity was imported, I opened it up, clicked Edit, and added my mother and niece to the "Scheduled With"
4. I then clicked on the Location field, typed "Denny's" and several suggested locations popped, and I selected the correct one.
5. The last step was to scroll down to the bottom of the activity and select "Send email invitation", and clicked done.