This is a good accessibility feature for blind or visually impaired users. All too often, any sort of touch screen device in a hotel has not been configured with accessibility features. Especially being able to turn on and off the lights, and adjust the thermostat with ease will be helpful. Many different kinds of Thermostats and light controls are found in hotel rooms, so this feature will make it faster for blind and sighted users alike to very quickly access these controls without having to learn an interface per se.
I wonder if these iPads can also have the full featured VoiceOver screen reader activated, or if they are locked down? This would enable a blind user, for instance, to sign in to their iTunes account. VoiceOver can typically be toggled by saying to Siri "turn on VoiceOver," or "Turn Off VoiceOver."
I've wondered also for a while why hotels have not outfitted rooms with the Amazon Echo with Alexa which provides a lot of voice activated features out of the box and through skills. The Amazon Echo with Alexa also provides good nonvisual accessibility.