Cursor is an AI-powered code editor (built on top of VS Code) that helps developers write, edit, debug, and refactor code faster with built-in context-aware assistance.
It is valuable because it helps you move through the entire development workflow faster:

Use Tab in Cursor to accept smart autocomplete suggestions that predict the next lines, repeated edits, and likely code changes as you work.
Use Ctrl/Cmd + K in Cursor to edit selected code with natural language, letting Cursor instantly rewrite, refactor, or improve it based on your instruction.
Use Ctrl/Cmd + L in Cursor to chat with your codebase, ask project-level questions, trace logic, and understand how your application works.
Use Ctrl/Cmd + I in Cursor to plan and apply multi-file changes, making it easy to build features and refactor across your codebase.