Happy to see propTypes getting shelved. Too many people stubbornly use propTypes even in Typescript projects. Hopefully this change will usher in the final stamping out of that.
I've been using Flow in my React Native app, but I still find PropTypes very useful, because warnings pop up in the iOS simulator whenever a prop is invalid. I think it's important to have both compile-time and run-time checks.
I recently (5 minutes ago) discovered 'flow-runtime' [1], which gives you the best of both worlds. It automatically generates PropTypes from your Flow types, as well as checking all of your other types at run-time.
In a non-Typescript project, they're a shoddy half-baked type system duct-taped together. In a Typescript project, they're almost completely redundant, they add a huge maintenance burden for basically no gain.
I recently (5 minutes ago) discovered 'flow-runtime' [1], which gives you the best of both worlds. It automatically generates PropTypes from your Flow types, as well as checking all of your other types at run-time.
[1] https://codemix.github.io/flow-runtime/