I can hardly imagine a situation where you need really modern JS in old browsers + mostly static html+ css pages. http://vanilla-js.com is here for a long, long time, as well as https://caniuse.com/

It seems to be a setup for small projects with homemade CSS + tiny JS libraries (like slideshows or carousels). Why not, it makes sense, especially if you have multiple sites with this build, but c'mon, you can just write ES5 and it will work everywhere.

PS Personally for such setups I'd prefer vite + svelte + tailwind. Or just vite + JS/TS. Or Preact if I need more reusable components. Webpack is for sure not the best option.