Mac ANE is on demand, and uses not only for Siri but also for finding objects in images like landmarks, pets, plants, books, and flowers using the Photos app or Spotlight search; Getting additional information about recognized objects using Visual Look Up in places like Safari, Mail, and Message, detection of faces and objects on video in apps like Final Cut Pro and automatic cropping with Center Stage, background blurring during FaceTime video calls, providing optical character recognition (OCR) in Camera and Photos, allowing you to easily copy handwriting or text like a Wi-Fi password or address from images, memories curation and stylistic effects in Photos, personalized recommendations like wallpaper suggestions, VoiceOver image captioning, finding image duplicates in Photos, etc.
I would concern if it doesn't always keep close to 0% if not in used.