This illustrates the significant difference between the use-cases of "web APIs" and conventional APIs, that the former are more like a database CRUD (including

This illustrates the significant difference between the use-cases of "web APIs" and conventional APIs, that the former are more like a database CRUD (including REST), rather than a request for computation. They (usually) are an alternative interface to a website (a GUI), and that's how most websites are used. e.g. an API for HN would allow story/comment retrieval, voting, submission, commenting. They could be used for computation, but (mostly) aren't.