I don't know ANYONE that would go for that $15 package as the MAIN TV programming, theres next to nothing in it. Particularly if its true that the locals are not in it either.
Then you probably don't know any cord-cutters. Look, there a lot of younger folks out there who no longer even watch traditional TV channels. Netflix, YouTube, maybe HBO, and they're good. Some of those folks would be happy to add an inexpensive package of channels that gets them CNN, TBS, TNT, plus lifestyle programming from HGTV, Food, scripted series from AMC, etc.
And then there are cord-cutters who already get their locals for free with an antenna. This $15 package would make a very nice complement to that -- think about it, it would be a lot like what cable TV looked like back in the 80s, back before the number of channels exploded. Is it for big sports fans? No, since there's no ESPN, FS1, NBCSN, various RSNs, etc. But half of the US viewing public doesn't care that much about sports anyhow. And keep in mind that AT&T lets you add HBO to their packages for another $5/mo. If that extends to this new $15 package, wow, that's a great deal. (Also, this $15 package will be free for AT&T's most expensive unlimited mobile wireless customers.)
Imagine if AT&T followed in the footsteps of Sling TV, which offers the $130 AirTV Player that lets you integrate local OTA channels with Sling's streaming channels. If there were a similar device that you could buy for DTV Now/AT&T Watch, you could conceivably pay just $20 a month for your local HD channels plus HBO, CNN, TBS, TNT, and maybe 30 other popular channels, and all of it would be integrated into one UI on a single box. Plug in a USB hard drive to record the OTA stuff and use cloud DVR to record the OTT channels. If executed and marketed properly, that could have huge uptake.