Why I’m still using @lit/react despite React 19’s Web Component support

React 19 finally brought native Web Component support to the finish line, achieving a perfect score on Custom Elements Everywhere. However, after rewriting AgnosticUI with a unified Lit core, I discovered that "support" and "Developer Experience" are two very different things. While you can use standard Custom Elements in React 19 now, I’m still opting for @lit /react for these three reasons: The Event Mapping Tax: React's synthetic event system still feels clunky when listening to standard DOM events. @lit /react handles this mapping automatically. Prop vs. Attribute DX: Passing complex data (objects/arrays) as properties rather than stringified attributes is still more ergonomic through a wrapper. TypeScript Definitions: Getting high-quality Typings for a raw Custom Element inside JSX is still a manual chore that @lit /react automates. Furthermore, moving to a "Source-First" architecture makes components more AI-readable, allowing LLMs to refactor code without the "black box" halluci