I tried one of these out and it worked so well I've bought another half dozen. It wasn't obvious at first but these sensors actually measure 3 values - motion, light luminance (lux), and temperature (celsius). By measuring the luminance the Philips Hue app cleverly only turns on lights when there is motion *and* it's night time. Installation using the Philips Hue app was too easy for words - it even asks you which light to control and sets up all the triggers and values, so it just worked. As a bonus I now also have the temperature of the room on my iPhone.
The lights on my stairs and in the entrance now turn on automatically. No more fumbling for light switches in the dark while carrying bags. But didn't have to pay an electrician $$$ to install, just stuck one of these to the nearby wall using the magnetic attachment.
Also works great in the Elgato Eve app and Apple Home app.