As a follow up to this discussion:
I met with the manager of the Apple store where the sales associate told me that the Apple TV would allow me to view my iTunes movies on my iPhone 6 Plus, without asking me if I had wifi. The manager admitted that this has been a past problem with many associates--telling customers that it would work without asking then if they had wifi. Contrary to popular belief, as large number of Apple customers DO NOT have wifi fi.
He admitted that customers come into an Apple store and believe that the sales associates, who are referred to by the term: "Genius," do not always ask specific customers questions to better qualify them for the products they buy.
Apparently, this has happened many times before at many Apple stores, and as a result, the managers of Apple stores are re training their people so that this does not happen again.
The assumption by commentators here on this forum that people are well informed before they go into an Apple store is not true in a majority of cases. It is a fact of human n nature that people go to an Apple store with the belief that they can ask a "Genius" questions and their answers are informed and truthful.
The manager told me that what they are supposed to do make certain that a particular device will work for the customer, when asked "will this work," not just say "Oh yeah, no problem."
Finally, this forum is precisely for the purpose of discussing these kinds of problems. There are many people who do a Goggle search for their particular problem and find this forum has "answers"under the search results.