It was one of those few 3rd party Apps that still worked. Apparently dev was in talks with Reddit in obtaining Paid-API-Access, but now they cut off his API-Access mid talks without informing him
It still works fine if you moderate a subreddit. If you make yourself a private subreddit and mark it NSFW, you can both use the app and the API will let you see NSFW content.
Of course I've tried it, that's how I know it works. I was just using it 5 minutes ago. I don't think it's going to matter if you used to moderate a subreddit, you need to currently moderate a subreddit. I literally moderate an empty sub I made in like the last two days, who I'm the only subscriber to.