"It allows AI to understand its physical environment and also to self-improve over time, without a human having to tell it exactly what to do."
In Minecraft, the team used a protocol that gave Dreamer a ‘plus one’ reward every time it completed one of 12 progressive steps involved in diamond collection — including creating planks and a furnace, mining iron and forging an iron pickaxe.
This is also why I think the title of the article is slightly misleading.