- Don't need to depend on a DI library, makes code more modular and portable.
- Faster application initialization time.
- Easy to navigate and understand relationships between classes, good IDE support.
- Easier to break apart and test parts of the application.
- Easy to understand, don't need to learn the intricacies of a complex DI framework.
I'm not saying there is no place for DI frameworks, although I do think they are overused.