I mean instead of adding polyfills for "fetch" api and "es6 promises" that brings a gazillion dependencies with them, one can simply add jquery package that has ZERO runtime dependencies(https://github.com/jquery/jquery/blob/master/package.json) and have ajax calls, promises and much, much more out of the box. I love jQuery.
1 dependency that's 34.6KB minified. That's a lot more than the two separate dependencies, and besides, once you've gone to the trouble of adding a package.json to add one dependency, adding one more is a very small step.