The service comes with access to popular apps like Netflix, Amazon Prime, YouTube and HBO, plus music streaming from Amazon Music, Pandora and iHeartRadio. Comcast recently added NBC Sports Gold packages, and since the service is relatively new, we'll likely continue to see additions like this.
Xfinity Flex is a lot like Roku, Apple TV or Fire TV, but there's no up-front cost for the streaming device, which also comes with a voice remote. That might appeal to new cord cutters who aren't as experienced with managing their own internet TV experiences and are more comfortable with longstanding services like Comcast. For Comcast, providing Xfinity Flex to all of its internet-only customers boosts its subscription numbers, and it's likely hoping that internet-only customers will like Xfinity Flex so much that they'll upgrade to Xfinity TV on X1, which, conveniently, they can do from the Xfinity Flex guide.