I think one thing to keep in mind is that just because something is available in the browser, that doesn't mean that all other approaches are suddenly moot and will never be able to displace it - XMLHTTPRequest is also still available, for example, but did get replaced by `fetch`.

But in general, you raise a good point - just because something worked well with developer tooling, doesn't mean that it would work well when integrated in the browser. You see the same e.g. when people are calling for runtime type validation in the browser just because they like TypeScript, even though the pros and cons would be completely different.