Roku has made a move to defend itself from the rise of Voice Assistants everywhere, enhancing its Roku Connect and operating system and announcing its own Roku Entertainment Assistant, a voice system for smart speakers. Its vision for voice seems to be to continue to have a viable option purely for entertainment, rather than the grander vision of Amazon’s Alexa to extend voice control to every device in the home. Its vision is really about controlling what comes out of smart speakers, the TV and sound bars connected to the TV, using voice. It will show a product from TV partner China’s TCL at CES next week, the first to use this system. It’s a conservative, low level approach to…