Not much for encrypted data, but they can still get metadata out of it (which site you visited, how much traffic was exchanged relative to other sites you visited, what times of the day you visited, which days of the week you visited, usage patterns, etc.). For example, if you have a pattern of visiting say, an Amazon store, that information could be useful to have rivals of Amazon to target you with ads or special offers, even if they cannot find what exactly you did on Amazon.

The voice calls are also on LTE (VoLTE), and a similar DPI scheme could be used to get a lot out of that by recording and inspecting content and metadata. Legality aside, if they're intent on mining data, there are millions of people who wouldn't even know what http vs. https means or to use end-to-end encrypted apps for calls, etc. (or probably not care as much). I'm not implying that nobody will care, because there may be another prominent movement (savetheinternet) like the one that helped block Facebook's Free Basics initiative through campaigns and well crafted letters to the authorities.

You are missing that also meta data such as the connected host, the time spent on a connected host, time of access, data volume transferred etc is also valuable. Also, they know the subscriber pretty well to begin with. Also their location.

Also, lots of sites are not encrypted, still.