If you have been playing minecraft for a couple of years now you probably played in many worlds built a lot of cool stuff and had long long sessions of caving in them, how cool would it be to know how much time you spent, blocks built/broken , times died throughout your entireminecraft career
WHAT I RECOMMEND :
*Having both per world(same full stats, no changes) and global statistics , global statistics being less detailed and more focused on the important things like total time played , travel distance, mobs killed , etc...
*Possibly have the global statistics connected to your minecraft account and can be erased if a player wants to. (shouldn't be a problem since the stats file is only a couple of kb and when reduced to a more focused stats with way less data it will be very small)
Before 1.7.2 Statistics were global for the game but currently it's per world Statistics and it should be changed
*note incase anyone misunderstood : I do know the previous stats can't be known since it wasn't tracked.