Stream question

Hi, I have internet services from Comcast,  no TV nothing else. I noticed that if I sign into my account and go to Xfinity Stream there are some movies and programs available to stream. However Comcast rep told me that Streaming is only available to TV costumers.  Can someone please explain to me how streaming services work at Comcast? I just wanna make sure they won't charge me more for anything.  Also One of the stream sections is called "On Now" basically it is streaming stuff live, does this go against my bandwidth? 

Thanks