The trouble with Linux is that anything you don't vendor in will be a giant fucking headache when it comes to support. But then, so will anything you do vendor in, as soon as some shared lib your vendored-in dep relies on is at the wrong version, or when it encounters some oddball config/package combo, or whatever.

Here they appear to have chosen to vendor in the whole damn OS, which, given the realities of supporting Linux, doesn't seem totally insane to me. I'd expect it also lets you run it with reduced permissions (not everyone has root on their workstation) and to generally make cross-distro operation much more reliable and consistent.

Maybe you want to run a completely different kernel, or distro, from your prod environment.