I have the same philosophy when it comes to bundlers and transpilers.
With the browsers developer tools being so awesome a debugging (and prototyping) environment, I feel having a 1:1 with what I write and the devtools is very strong. I know source maps can mitigate some of this, but for me it's more of a hassle than a benefit.
Anyway, great write up! I have linked to this post in my own recent post (shameless plug incoming) about documenting a callback: blog.birk-jensen.dk/documenting-a-callback-functi…