VDG is used to pay for transactions and to send data to the blockchain. The utility token covers the fees that are associated with creating a new record, such as gas on the Ethereum blockchain.
Gas is a special unit that quantifies the amount of work needed to perform actions on the Ethereum blockchain. Much like a car which requires a certain amount of gas to get from Point A to Point B, actions performed on the Ethereum network require a certain amount of gas to complete.
In addition to using gas to perform computations, gas is also used to pay miners who provide their resources to the Ethereum blockchain, in the form of a transaction fee.