Dove into this when I flashed my AirGradient device. At first I had a hard time understanding how everything integrated together (does ESPHome need a hub? how does HomeAssistant work with this?). After (mostly) figuring things out I discovered how powerful it is to have configurability ranging from OTA updates to MQTT support.

My only gripe right now is the lack of documentation and confusion on the HomeAssistant side. The ESPHome addon turned out to be a red herring for getting everything set up.