Hey there,
2 things here:
I just wanted to hide my Error page from the Panel and experienced a bug that was already described here:
It seems that you can not hide a page, when the blueprint site.yml has set pages: false.
Also when you set pages to false and click on edit something calles on NULL. See gif below.
You can also see in the gif, that the error page gets visible as soon as I set pages: true in the blueprint site.yml
Tested on kirby /panel stable and kirby development branch
Why would you want to set pages: false on site? Maybe it’s a bug, but site cannot have no pages, because home and error are default pages, which cannot be deleted.
If you want to disallow adding any more pages, use the max option.
Well if you have a fixed amount of pages that exist and you don’t want anyone to be able to create more of them on the first level of your folder hierarchy, then it makes sense to restrict the page creation by disabling it.
In my case I have a one-pager that has a strict set amount of pages that structure the site into sections. You then can expand and append content to those sections but you should not be able to add more “main-pages” but just “sub-pages”.
So I don’t want to have “no pages” but I don’t want to have any further pages 
That’s why I suggested to use the max option instead of setting pages to false in general, which is actually the correct setting for your use case, not pages:false.
