I spent an hour last night fixing all my local files not being playable on the iphone app and I wanted to let people know what's up in case anyone else has this problem.
All the files that wouldn't play A) weren't greyed out on the app, so I had no idea that they were being skipped and B) the problem was that the metadata had a title. When you save a music file, you name it, and that's what you see in window's file explorer. There's also a place for a, "title" which is usually just the name again, immediately to the right (again, in file explorer not in spotify). Spotify wasn't playing or greying out anything that had a title.
I'm not looking for a solution; I just thought I'd put this out for general information and to complain because this is stupid and just another installation in the saga of me fighting to keep my local files playable.
And while I'm here I'd like to say that besides everything I'm really glad spotify has this feature, and if you guys ever get rid of it I'd probably go somewhere else.