[thewizardofmys]

I see some potential use of this, for example as soon as Google crawlers reach the site I know that it is accessible from outside and I destroy the site.

[placeybordeaux]

That seems to be the exact use case. Did you want to elaborate on why you find that useful?

[aqme28]

What is the purpose of a website that is inaccessible "from outside"?

[jessaustin]

Maybe it's a resource that should only be used by people in a particular organization?

[kordless]

It's not a purpose. It is a detection of state, however.