Totally fair — this pattern can be confusing at first glance. The main motivation is ease of integration: no need to manage extra .c files, no build system tweaks, just drop in one file and go. It’s especially useful for embedded systems, scripts, and small projects where build friction matters. That said, I agree that for larger teams or long-term projects, the classic .h + .c split can be clearer — that’s why the implementation can easily be separated if needed. Appreciate the feedback!