From Ecobee’s explanation of the feature:

If you’re on a Time of Use rate, the price of electricity is higher during peak hours of the day. Thankfully, Peak Relief is a new feature on your ecobee thermostat providing you with an easy way to save money and use less energy by automatically heating or cooling your home when electricity is less expensive.

With Peak Relief, you can save money without ever compromising your comfort.

Ecobee owners in select markets can enable the feature in the mobile app.

My electric company doesn’t charge different rates during peak usage time, but if they did, I’d certainly be excited about this feature.