One argument is that Javascript-in-the-browser has advanced a lot and there's less need for a build system. (ex. ESM module in the browser)

I have some side projects that are mainly HTMX-based with some usage of libraries like D3.js and a small amount of hand-written Javascript. I don't feel that bad about using unpkg because I include signatures for my dependencies.

npm is a package manager though, not a build system. If you use a library that has a dependency on another library, npm downloads the right version for you.

Yep. And so does unpkg. If you’re using JavaScript code through unpkg, you’re still using npm and your code is still bundled. You’re just getting someone else to do it, at a cost of introducing a 3rd party dependency.

I guess if your problem with npm and bundlers is you don’t want to run those programs, fine? I just don’t really understand what you gain from avoiding running bundlers on your local computer.

Before ESM I wasn't nearly as sold on skipping the build step, but now it feels like there's a much nicer browser native way of handling dependencies, if only I can get the files in the right shape!

The Rails community are leaning into this heavily now: https://github.com/rails/importmap-rails