Did you read my last point about "a way for Home Assistant based HVAC control setups to work with energy company savings programs where appropriate" ?

Unless you're living off-grid, I think there's still some benefit to having one of the largest energy loads (building HVAC) coordinate a bit with utilities to ensure there aren't blackouts and such. Even better if there's an approach that works with open-source solutions like Home Assistant.

Where I live staring at the grid load and available energy is a thing during heatwaves and other inclement weather, and the utility generally issues "energy rush hour" limits to smart thermostats to help ensure grid reliability. The utility also incentivizes this I think by providing a small discount on the utility bill.