Minecraft is the most creative game on the market!
Although it is only a mock 8-bit game, the game has no limit on creativity. Before creative mode came out (at least on the Xbox version) it was really difficult to “harvest” rare items (without cheating). Even now, if creative mode is enabled, achievements are locked and therefore you can’t jack up your gamerscore.
This glitch (shown in the video) allows you to “harvest” rare items without creative mode enabled and in turn will help unlock those achievements!