I worked for Spotify very close to this integration. Not going into too many details, but the access they got is generally what's being reported. That said, I'm

I worked for Spotify very close to this integration. Not going into too many details, but the access they got is generally what's being reported. That said, I'm not aware of Spotify doing anything with messages other than displaying them to users; they weren't mined for data or retained. The intent was a unified messaging experience across apps, but it's been effectively dead for over four years. The only creepy thing I'm aware of that they tried with Facebook data was try to build a taste profile from "likes," and this is from public profile data. There's a big difference between what the permissions could do and what they were actually used for. Facebook takes its contracts with trusted partners as seriously as they say. My concern would be less around "how was my (let's be honest--Facebook's) data used" and more around Facebook's growth at any cost engine. Or the overall growth engine of tech.