What is a hub?
In the context of a home automation and smart homes a hub is a device that is designed to coordinate home automation devices. If you search for a hub on the internet you will find articles that call all kinds of devices hubs. I have seen Amazon's Echo devices called hubs. The majority of these devices are not hubs at all as they do not allow the devices to directly communicate and coordinate. That is after all the point of any level of home automation, to have something do something automatically. The majority of these devices work out to a very expensive remote. If you are looking for true home automation or to a further extent a Smart home most of these devices are not going to help at all, they may even make your goal more difficult. As a general rule if the primary bragging point of the product is how it interfaces with you, it is not a home automation or smart home hub. The fact is that many of these devices that are billed as a hub, need an actual hub to function. A hub contains the hardware needed for the devices to communicate with outside protocols as well as the needed hardware and software needed to coordinate the devices.