I so far agree with all you said and strong think already based on limited info available to me that you are a well-versed Elixir dev. However nothing beats the short term dev speed of scripting up some JS with npm. Have you seen the latest test runner efforts on node.js and advancements in deno? I think this gap is slowly closing but node is still not near Elixir in terms of long-term productivity, in future it will take over though I think if types dont get into the Elixir language fast.