The Apple TV (2015) can be used as your Apple HomeKit hub so that you can remotely control and automate your HomeKit devices. However, you can't directly control any HomeKit devices from the Apple TV and you still need to connect it to an external TV.
Fortunately, Apple also lets you use the iPad as a HomeKit hub - not only does the iPad serve as a remote access bridge that can support HomeKit automation, you can also directly control your HomeKit devices. The Apple iPad Pro is a great option for this given its display which allows you to monitor and control everything that is going on in your home.
The Henge Docks Gravitas is a convenient way to keep the Apple iPad Pro powered and upright in a stable base. It has an Apple Lightning cable that you can plug into a USB AC adapter to keep the Apple iPad Pro powered, allowing it to keep your HomeKit devices connected to Apple's servers in the cloud.