One thing frequently overlooked by newer worm farmers is the importance of carbon material in vermicomposting.
When we first set up a worm bin carbon serves as our bedding. Bedding provides a safe haven for worms in case something goes wrong. A lot of wormers never add more high carbon material. The result is a wet, muddy casting that turns to a hard lump as it dries and is almost impossible to sift. Adding drier carbon material when feeding is a good way to control moisture and helps create a more granular, pleasant looking compost that's easier to sift.
Higher carbon material takes longer to compost and provides a longer term food for worms if you're vacationing or miss a feeding or 2.
Perhaps most important is carbon materials feed fungi. Fungi is lacking from most agricultural soils. Fungi is important for most plant growth and for creating aggregates in soil. Long term fungi improves water retention and conversion of minerals and nutrients to a plant available form.
These are a few reasons why carbon materials are important to worm farms.