A:Answer My understanding is that it will, once the streaming service is providing 4K content. I do not believe they are doing so now. The Chromecast doesn't stream the content "from" the phone, exactly; it uses the phone to connect the Chromecast to the provider over WiFi. Supposedly, your phone or device doesn't really do anything once you cast, so if it loses connectivity or the battery dies or something, the video still plays. Basically, the device's computing power or bandwidth or whatever the right term is would not be a limitation of the quality of content you can stream.
