Nodes vs Servers
Decentralization sounds good philosophically, but it's also just better design.
Why Deploy to Lots of Computers?
Besides the philosophical drive to include more people in the wealth creation of the web, there are a number of reasons that new web startups might want to consider decentralization in their roadmap.
Centralized ownership and control create vulnerabilities by introducing unnecessary single points of failure.
Marketplace dynamics can ensure compute costs stay low as networks scale. When hosting is decentralized, projects can dynamically reprice and ensure competition for the lowest cost.
Privacy is enhanced when there isn't just one core server IP address by allowing lots of devices to serve network requests and thereby hide the traffic from would-be snoopers.
Protecting Tokenized Assets
Tokens or NFTs can be exploited if there is a master key or an app server that manages the smart contracts. If a Web3 project promises inflationary token rewards to support their hosting or network participation (such as utility tokens) then the issuance of new tokens cannot be controlled centrally or participants have no guarantee of fair treatment.
Data responsibility and portability
Despite the introduction of GDPR and similar legislation, large apps tend to end up owning a lot of user data. When this content and identity information is decentralized on open frameworks, users are free to migrate from one platform to another, and developers are freed of the obligation of data stewardship.