The K1 hub can be placed anywhere you like. The K1 hub shows the status using the light up ring at the back. It might be convenient to place it anywhere you would like to be able to see the alarm status.
On the other hand it's needed for the K1 hub to receive all connected accessory signals. It is recommended to use the testing mode in the K1 app to check the signal strength of every accessory as soon as both the sensors and the hub are on the place you would like to have.