One could also ask why you'd need parcel if you're already writing modern es module code. If you really need to bundle that (and you kind of don't, es modules allows you to put each requirement in your page html, and get the benefit of browser caching for individual pieces of the pie back, which you lost when you starting bundling and single-line changes to a single small class created entirely new hundreds-of-kbs bundles) use rollup.

If you know you're targeting modern browsers, the need for bundling is slowly disappearing again. And if you're targeting something like electron, there is _really_ no need to bundle because you're distributing the entire filesystem with load times that don't involve network requests.