Working in somr Architecture University, we produce and manage lot of large format layout.
In Designer as in Publisher, Colour separation is very important (to control real gray scale for instance) and working with a full CMYK commonly used.
I check many documents with illustrator (easier that indesign) to check colour space, true black, bitmaps resolution and so on in a document.
As many here, I mean such tools are perhaps dispensable in a hobby work, but not in a professional work if you want to be concurent with Ado...(you know!)
An sure we'll enjoy to have some professional alternative to "major" editors ;-)