If they could I believe they would. They rather not be reliant on whoever is providing their speak recognition.
Apple has their own speech recognition tech.
"Local model" means the voice snippet is processed on your device. Never beamed off to a server farm.
The interpretation might be:
Action: internetSearch
QueryString: movie times for "Avengers" [near me || {userPreferences.movieTheater}]
UseLocation: true
Which then kicks off whatever process Siri has for handling internet search actions