The main reason you pack scripts is because you're compiling, and your compiler is checking and optimizing your cross-file interactions. For example, you need to merge scripts to be able to detect and delete unused functions, because otherwise some unmerged script might call the function without the compiler being able to detect it.

> Instead of downloading the entire app before users can use it, code splitting allows you to split your code into small chunks which you can then load on demand.

You need to make a business case that your whole application is modularly composable.

Some application might fit under this umbrella, but there are other stuff that don't, like a pdf-render, or something like google slides, which as I just checked, the core editor js is bundled in a single js file and as large as 1.4MB.