Disclaimer: Participation in any SNS is at your own risk.
DAOs are a growing form of organization for accomplishing goals. For example, in the ETH ecosystem, Uniswap and MakerDAO are popular DAOs with billions of dollars locked in their respective smart contracts. However, ICP is unique in that it can host fully-on chain dapps (frontend, backend application logic, and data), so SNS DAOs are unique in that they can fully control (via voting) every aspect of a dapp, since everything is on-chain.
Having fully on-chain DAOs is important because it enables all decisions to be executed on the blockchain. This is in contrast to existing DAOs on other blockchains where voting takes place on-chain but the execution of the results are often carried out by developers off-chain. This facilitates true decentralization.
Therefore, SNS DAOs serve as a vehicle to deliver fully decentralized online services that are owned and governed by their communities.