No one likes to set up or update things. But when everything is coupled (why not even include a framework in Bun?), you are even more dependent on choices made by them and will be forced to upgrade no matter what. For example, if they decide that their implementation of the test component wasn't good enough in version X and they completely reimplement it in version X+1, you will have to upgrade your code, but maybe at that point you don't want to rewrite all your test suites, you just want to get the new http3 request handler, but you still must rewrite all your test suites...

When things are not that coupled, independent components you bring together, you can update the webserver, and/or some components, and keep the old version of the test library for now, until you decide it's time to upgrade.