> Why reinvent this wheel, adding complexity, bug-surface, maintenance burden and whatnot to your project? What problem dies it solve that hasn't been solved by other people?

Whilst this is (effectively) an Argument From Authority, what makes you assume the Node team haven't considered this? They're famously conservative about implementing anything that adds indirection or layers. And they're very *nix focused.

I am pretty sure they've considered "I could just run this script under a different user"

(I would assume it's there because the Permissions API covers many resources and side effects, some of which would be difficult to reproduce across OSes, but I don't have the original proposal to look at and verify)