Vim’s modal design enhances text editing efficiency. It separates command input from text input, reducing the need for mouse usage or complex keyboard shortcuts. Normal mode allows navigation and manipulation of text blocks, while Insert mode is used for typing. Visual mode enables selection of text areas for operations like deletion or copying. Command-line mode facilitates file saving and quitting Vim. This separation of modes reduces errors and increases speed by assigning specific tasks to each mode, making it a powerful tool for programmers who require precise text manipulations.