scrolller still works I think. However, its only useful if you're looking to just browse images and videos (as some might do on porn subs). If you're looking for a way to read and interact with posts, I dont think there's a way through the API anymore.
The subreddit for the Boost-client found out that users that are mods within any subreddit can apparently still use the app (maybe with the patch where you use your own API key instead of the one the app uses). Maybe if you created your own subreddit and marked it nsfw, you could still browse those subs with Boost, but thats just me guessing.
Depends on the measure.
By GDP? No
By GDP adjusted by PPP? Yes