Thank you. I was a bit surprised by the mp4 container (instead of matroska), as well as DTS not being allowed. Now it all makes sense, and it's not really a big deal at all.

SD content is mostly being used on smartphones and tablets. For iOS users, this would require a lot of extra work to convert the files to the limited container choices.

A part of me would like iOS users to deal with the inconveniences of their more locked down platform, and also show some love for matroska. Conforming to restrictive policies is a good way of allowing restrictive policies.