I suspect this is more relevant for people who aren't normally JavaScript developers. (Let's say you use Go or Python normally.) It's a way of getting the benefits of multi-language development while still being mostly in your favorite language's ecosystem.

On the Node.js side, it's not uncommon to have npm modules that are really written in another language. For example, the esbuild npm downloads executables written in Go. (And then there's WebAssembly.)

In this way, popular single-language ecosystems evolve towards becoming more like multi-language ecosystems. Another example was Python getting 'wheels' straightened out.

So the equivalent for bringing JavaScript into the Python ecosystem might be having Python modules that adapt particular npm packages. Such a module would automatically generate JavaScript based on a particular npm, handling the toolchain issue for you.

A place to start might be a Python API for the npm command itself, which takes care of downloading the appropriate executable and running it. (Or maybe the equivalent for Bun or Deno?)

This is adding still more dependencies to your supply chain, although unlike a CDN, at least it's not a live dependency.

Sooner or later, we'll all depend on left-pad. :-)