https://www.reddit.com/r/redditdev/comments/13wsiks/api_upda... and
https://www.reddit.com/r/modnews/comments/13wshdp/api_update...
Reddit really buried "no nsfw outside official reddit apps" (from the end of your first link). Didn't Tumblr do something similar and lose a significant fraction of its userbase and revenues?
I assume they hope to attract more advertising money this way.
There was a few months where it was required, but it isn't anymore.