I recently got to watch someone spend nearly a full week fiddling with building a React app for filling out a form for submitting a batch job on an intranet site. It's a lot of code, and it's non-trivial to understand how it works, what with all the async methods and clever state management and whatnot. It needs to be built, which is a thing, and building it requires having the right environment setup. (Its build speed reminds me of my C++ days, too.) I wouldn't be surprised if someone's already talking about incorporating Docker into its future.

At least to me, that's a rather arresting amount of time and money to see being sunk into a job that could have been accomplished with a simple HTML form on a static page.