The SmartHub is an extra module to use the outputs of your Jablotron control panel as inputs for Home Assistant, but also for IFTTT. Now you can give all existing sensors of your Jablotron alarm an extra function, for example controlling lamps etc..
Home Assistant (HA) is an open source home automation platform in the same category as Domoticz and openHAB. The Home Assistant platform has a huge number of native integrations and a large community with additional integrations for so much more connected devices. Most of the community integrations are delivered through the Home Assistant Community Store (HACS).