Right, there's a handful of cross-platform toolkits that are in widespread use as well. There's still a difference to full-on web apps though, in that web apps might run on platforms the developers never intended them to run on. The API is independent of the underlying system which means that any platform can implement a runtime environment (browser) and execute web apps without recompilation (kinda like Java but Java is barely used like that anymore).

Arguably this doesn't hold true for Electron/Cordova, so RN is probably comparable to that.