I almost never use it myself, but I get called upon to deal with it for some of my relatives. The fact that you can't just mount the file system on a non-crippled computer and transfer files to and from the device just drives me mad. Getting someone's music into the right place if they don't have access to a machine with iTunes is miserable. When the "files" app appeared a few years ago, I thought "finally, they'll let you manipulate files directly", but no - it's just another silo too restricted to be of any use.