By default Iris will try to automatically find your location. This thing is done only once and location services are not used. Basically you will not get battery drain or more CPU usage.
The Location is used to automatically gradually adjust Iris. Based on your latitude and longitude sunset and sunrise are calculated and with the help of the current time there is gradual interpolation of Color temperature and Brightness.
One thing I want to note is that this info is not send to the Server and nobody is seeing your location. It’s just shown for your convenience.
Actually everything in Iris is anonymous. Even the activation codes are not connected to names or e-mail. Everything in Iris is local, secure and anonymous so don’t worry about your privacy.
If you are under VPN or the location is not detected correctly you can set it to manual via the Location page.