A Harmony smart hub just needs to be basically nearish your IR devices. The signal bounces off the walls, so you don't need to be in line of site as such. The extra in line blasters are more for if you keep all your AV devices are inside a cabinet door, so you can put the smarthub inside with them, & run an extra blaster outside the cabinet to also control your TV on top. You CAN get Alexa to do specific device commands, rather than starting merely activities etc, but it is a bit of a convoluted setup using multiple services, and an android device as a server. I'm a bit of a tinkerer and got it all to work, but hardly ever use it as there is a bit of a lag. It will be good if Harmony do make it directly compatible, but I hope it amounts to more than just triggering activities.