Basically, because Brett expressed an interest in the format being standardised, so that VS Code could support it in some sort of “add a dependency to this script” action. So there is an interest from other tools in supporting scripts that declare their own dependencies, but only if it’s standardised (which is something I can understand, pip has a similar policy).
Not really. It’s come up a few times, but people seem to keep missing this point - the target audience is people writing scripts where the important point is explicitly that there’s no need to have a “build” step, they are just “write and run”.