The most likely reason they are not doing a free preview right now is where all the features of Epix isn't available only the linear channels are. Its also worth noting that Epix still isn't available for DirecTV Now yet even though it was part of the deal. This also lines up with Epix not being available to stream via the DirecTV app right now. My friend who works at the local call center advised me that a free preview of Epix is currently scheduled for July 19-August 17 which aligns with the premiere of Pennyworth. If the launch of Music Choice is anything to go by those were added on 2/10/18 and it took until 4/22/18 before D* subs could use the app and 6/7/18 for the website. So if you use the Music Choice launch as a rough guide then D* subs will possibly have access to Epix.com/Epix app by 7/19/19 which is when DirecTV's free preview of Epix is currently scheduled for.