Repetitive jobs are boring, and writing code is no different. Especially if that code is just a derivative of some data.
Software engineers create business value by thinking about systems that solve problems, writing code is our tool.
By using code generation software engineers are more productive and consistent.
Providing the specific inputs to the generator and invoke it is significantly faster than writing the code manually, therefore code generation permits to save time.
Because code is generated from an abstract description, the description becomes the source of truth, not the code. This makes it really simple to evolve the abstract description and generate new code for the application to run it.
Generated code is consistent. You get always the code you expect. The quality of the code is consistent. With code written manually instead you can have different developers use different styles and occasionally introduce errors even in the most repetitive code.
All generated output has been production tested before becoming a generator. As a plus, all generated code comes with good formating, provided by Prettier.