The PlayFab built in event "player_device_info" sends a lot of useful info regarding the player DeviceInfo. This kind of info is not included in any other event, but we would love to be able to filter our custom events by e.g. EventData.DeviceInfo.OperatingSystem and such.
I'd love to know, for example, how many players complete our tutorial (we send custom events at every step) based on the game Version (to see how changes in our code perform) or iOS versions.