If the police stands in front of my house with a warrant to search my belongings, can I refuse that? Does it make sense if I have nothing to hide?
The recordings of the water meter is more interesting and the possible combination with other devices, including the Echo. In case of a housing with lots of IOT-Devices the police could reconstruct the actions within based on the stored information, like when did someone eat, turn on the lights, wash hands, open the door, watch TV...