Resources will be required in-game to purchase items that provide unique utility. As an example, to catch a particular type of pet, say a butterfly, you might need a butterfly net. Or to access a certain area, you might require a mining pick to get through a wall. Vendors will exist in the world which you can trade resources with for these special items - which will also be represented by NFTs and tradeable on the secondary market.
Resources will not replace $WRLD as our main in-game currency. But they will supplement it for very specific use cases - providing unique and valuable utility to our land owners.