A benefit of a decentralized app is censorship resistance.
A benefit of a decentralized app is proof of user ownership.
A benefit of a decentralized app is trustless architecture, where smart contracts are hosted and validated by the entire network.
A benefit of a decentralized app is the ability to natively use the currency of the blockchain an app is built upon.
A drawback of a decentralized app is its slow speed.
A drawback of a decentralized app is that decentralization is its complexity.
Web2 consists of web applications that are built on an architecture that is owned and controlled by a single entity.
This is a more centralized way of creating web applications.
Web3 consists of web applications that are built on an architecture that is distributed among a decentralized network of entities. The technology used to decentralize the data is blockchain.