The question is not elisp v. vimscript but rather the power of not having to switch contexts. To write code for a locally-hosted RESTful API I used Chrome to read the API docs, Postman to make the calls, iTerm2 to start/restart the server and read the logs, and a text editor to make changes. I replaced that flow with eww, restclient.el (amazing!), multiterm, and an editor buffer. No changing of context, conserve about ~1GB RAM in Chrome instances, full-screen if I want it, and everything is text (I'm looking at you, Postman).
On the "highly custom" level, I have a work-in-progress script that takes a URL, sends it to a Splash server, and returns the rendered HTML to eww for viewing. This is great for annoying SPAs like the article that spawned this conversation.
My current goal is to swap out my development MBP with an eInk tablet and bluetooth keyboard. Success will be measured as a function of productivity and weather-/water-/environment-proofing of the device; the goal is productivity in full sunlight and/or under water. Emacs will have a central role in that. Just need to find an eInk device with adequate screen refresh rate and Bluetooth support....