Building vs. Describing: Why the Builder Pattern Transcends Simple Configuration

The Builder Pattern and Config Structs both solve the telescoping constructor problem, yet they embody opposite philosophies: Builder encapsulates construction logic to enforce complex validation rules (ideal for public APIs), while Config Structs prioritize transparent data containers (better for internal systems). Choosing between them means deciding whether to guide developers toward correctness or simply offer flexibility—a distinction that separates truly maintainable architecture from systems that merely function.