I'm with you conceptually, but I don't end up using Flipboard much if at all—and I understand I'm generalizing from a minute sample, so bear with me—because I don't find it to be the best way to read anything. For news/text, Instapaper is king, and for Facebook and Twitter, I find that the Facebook app and Tweetbot win out.
Is there a type of content that you find Flipboard excels at presenting, particularly on mobile? Or that "the Pinterest layout" does, besides Pinterest?
Well, I personally agree with you, but my significant other likes to view social network content through it in certain circumstances, particularly at the end of the day after getting in bed. But that's the saving grace of Flipboard; it's there if you want it, but it's not forced onto anything.
Is there a type of content that you find Flipboard excels at presenting, particularly on mobile? Or that "the Pinterest layout" does, besides Pinterest?