Tokens are the incentive layer of the Blockchain. The user must pay a gas fee whenever transactions happen on a blockchain. This fee is used to incentivize the miners/validators who have deployed electricity/capital to safeguard the network. This incentive layer is what makes the network decentralized. As an organization, one could set up a blockchain and do away with all the nodes so that no one has to validate the transactions. Such a system would exist without tokens, but then it won't be decentralized because the single node can conduct a 51% attack.