I've wasted so many hours doing the /etc/hosts + mkcert dance by hand and forgetting to clean up after. Having Pingora handle the proxy layer with longest-prefix routing and automatic cleanup on shutdown is exactly right. The CORS header caching from upstream preflight is a surprisingly thoughtful detail too, that one always bites you when testing against prod locally.
The main use case is browser-based debugging against a production-like client: the client keeps talking to the real domain, but specific endpoints are served by your local backend.