Regarding Extra Credits video -- that would be an interesting use for the blockchain tech, and it should be noted that there are already examples of this system, though its underlying ledger is an unknown quantity: Items in Valve's Team Fortress 2.

TF2's cosmetics or weapons you craft have your name as a permanent mark in their description. When additional single use permanent modification items are applied to them they can change colour, name and track the number of certain actions while the weapon/cosmetic is equipped (not just "kills", but things like "allies on extinguished") changing the items "level" in the process.
(I've not kept full track of Valve's games over the years, but I check in now and again to see what they're doing. Valve loves socio-economic experiments and I'm terribly fascinated by the subject.)

Handling a colossal database that has to keep track of the state of each instance of such items is an equally colossal undertaking and expense though. So for smaller and budget concious developers this is where blockchain innovation can play a vital role.