Siri on macOS is completely and utterly useless. I've had it enabled for a while but noticed I never ever used it, and wouldn't even know what to use it for. Ever. On my iPhone I use it occasionally to text my wife while I'm driving (usually to tell her I'd been stuck somewhere and will be home late) but nothing else. Navigation is pointless because it insists on using the useless Apple Maps application instead of Google Maps, and when trying to call people it usually gets stuck on their names, or forgets who I am every few weeks (so "call my wife" or "text my wife" doesn't work). To be honest, I have yet to find any use for Siri, Cortana, or Google Assistant. I've tried all three, and I consider all of them utterly useless at this point.
Unlike Open Casket I'm not saying I never will use Siri/Cortana/Google Assistant/Alexa but as of May 2017 I've disabled Siri on my Mac and Cortana on my Windows laptop.