I occasionally use layers set to suppress output for holding text that differs from the text in the visible part of a document that I need for variables or TOC entries sometimes, or for notes or guides I want in the file but I don't want printed. You might also want to suppress a layer with some sort of overlay, like the die-lines for a die-cut piece, when you export a PDF for screen viewing.
I'm sure you can come up with other reasons for having content on a page in the layout, but not in the final output.
Awesome!!!!! Thank you for your reply.