You can debug React apps just fine without the React developer extension, but in some situations it will be much harder. And to elaborate, I work on React full-time and just use the javascript console and debug messages for 99% of my debugging.
I honestly couldn't find anything remotely similar in my search for to unearth React runtime internals. Maybe I'm missing something but literally every answer was "just use the extension."
Same for React. If you are working on React itself, or you need diagnose an actual bug in the runtime then you'll want to use the JavaScript debugger and step through. If all you need to do is work out why your component isn't updating then you can use the React-specific tool (the extension) to make your life much easier.
Your argument is basically the same as saying you'd rather view HTML as a giant string rather than in a tree view... the devtools basically present something that's linear (the tree traversal) in a tree view, it's not that bad.
Can be as simple as that: familiarity.
I read this as a complaint that React doesn't provide information on what's going on that you can see and inspect (whether true or not). The equivalent for Postgres would be if they didn't document their protocol and instead referred you to a special debugger they provided, and you had to rely on that instead, making use of gdb or the equivalent much more complicated.
Also, the react dev tools aren't really a debugger. There's no way to step through code or similar. It just provides an insight into React's internal state (the component tree, and any state contained within it). The equivalent would be Postgres providing a tool to inspect the contents of its caches or indexes, and the OP complaining that they can't read them when using GDB.
[0]: https://reactjs.org/blog/2019/08/15/new-react-devtools.html
