The worst part of this is that the web platform is probably one of the most backward compatible runtimes in the history of computing. You can take some HTML/CSS/JS from 20 years ago and it will probably run just fine in a modern browser now. Build steps ruin this.
If you build a web application with no build steps, you could pick up working on that project a decade from now and not have to worry about not being able to work because of compatibility issues.