Rokus are streaming boxes/sticks that connect directly to streaming services (like Android TV). Next to the Amazon Fire TV devices, they're the smoothest way to get YouTube and other services on a TV.

My desktop is two floors away from either TV in my house, so being able to stream my personal media library to them over LAN is more convenient than lugging around a desktop to either TV. It's buttery smooth streaming too, and the interface is really customizable