If a TV supports images or videos, it's already pretty "smart", if it can browse the web and natively supports streaming services then it's a full-blown replacement for your usual media-oriented devices.What do you consider a smart tv? My tv is not labeled as a smart tv (no internet or apps), but it has played any video file I have plugged into its usb port.
Smart TV's aside though, people forget about simple convenience. A homebrew console app supporting streaming within LAN as well as HDD/Disc loading and controlled with the console's controller is simply handy - I don't feel like running back and forth with USB sticks or navigating menus with an uncomfortable TV remote just to get "semi-decent" playback, dedicated multimedia hubs or consoles with the right homebrew app for the job are just better in this regard, at least in my opinion.