Yes, I agree the performance is an issue in most use cases, but wouldn't you agree there is value in there being parity between WebGL and OpenGL ES? It's valuable for those of us who work with Emscripten to cross-compile apps for the web.

And there are things like line drawing algorithms that have uses for geometry shaders: https://github.com/paulhoux/Cinder-Samples/tree/master/Geome...

It's not like geometry shaders are specific to OpenGL ES. Desktop OpenGL has them, as does DirectX and Vulkan.