You are absolutely right. This worksHi Kiwi,
Been a long time since I have been on the forums, but like you, I have just started with HassIO over the past couple of months, hence this is how I found your post.
I run MP1 throughout the house and have a Harmony Remote Hub running in the Lounge room to control my Setup.
Basically, I can ask Google Home to tell Harmony to turn TV On/Off/Mute/Unmute at the moment.This happens via the Harmony IR commands. However, HassIO monitors the current state of the Harmony remote and sends a shutdown command to the PC or WOL command to start PC up. This weekend I am setting up some Sonoff's with Tasmota firmware to allow me to control the Sub Woofer power, and will include that in the turn On/Off script.
Eventually I want Google Home to send commands directly to HassIO to control Harmony Hub, but taking baby steps first due to Wife Acceptance Factor.
I am looking into building a plugin for MP1 that would somehow integrate HassIO with with MP1 so you could eventually send commands via Google Home to control your HTPC.
this way you could control certain things of MP1 via the HassIO web Interface, which also meant controlling it via Google Home. Not sure how well this will go, as basically I have jsut started thinking about it and searching to see if anyone is already developing something already.
I am sure there is a lot of work here to be done to integrate the 2 together - if it is even possible, but maybe its worth a try.