I am normally really protective with my data but I don’t get the outrage here. If the data is all about how you use the app and the report relates to things relevant to usage that are interesting and is sent just to you,I don’t see the harm. It’s not broadcast to the world and isn’t sharing a bunch of sensitive information (as far as I know). It just seems like a fun way to reflect on the year.
I use Pandora and I wish they did something like this. As much as pandora is all about data I would love to see a report on my music listening with some of their insights about music attributes included.