This is the an older one, but since the 1.9.1 is out, just a bit of my view.
The straigth visibility of EVERY object on the page should be the essential and a basic feature of any layout/publishing software. The reason is obvious - you need an absolute control of everything on the page to end up with correct and reliable output.
The question of this topic has been answered in a first 4 posts - it is not possible (yet).
And I have to agree with guys above, the rest are just helping workarounds (and excuses), which are working only partially, but mainly - slow down the workflow significantly.
It is not just about creating "empty" or "white" boxes and "why would you need them" (really??). They could be whatever - leftovers from previous designs, versions or while working on a design. That just happens! People do make mistakes and we all work under heavy time pressure, so having a objects on page you can't see is a straight way to hell. Because they allways affect other object on the page. Transparency is a "nice" addition to this. You need to know what are you doing, with what, and where it is.
I believe everyone here is on a tight deadlines, so the most important things in our everyday jobs are efficiency, usability and speed, and so is eliminating every possible errors. And this is the right opposite.
You just can't be serious here. Could work for something simple, yes. But right now I have some sort of catalogue in front of me, with more than cca 300 objects on the page - "data merge" driven tables, pictures, lines, small vector shapes + dimensions.. etc. (yes I'm in InDesign). Half of them are in white - texts and lines on a colored background and pics. Changing something on back (upon client request) could lead (and it does) to a massive ammount of invisible objects on a (white) page. There is no way to handle them because I can't see them. Trying to locate them in the layer panel, Ctrl/Cmd + A, delete them all and start over, create temporary colored box under? Switch to Designer? There's no time to play games here....
Many uses for them. They are here to help you, not to be printed (or visible in final design).
Depends what are you working on. It can be done in different ways but speed and efficiency is the key.
Maybe for creating an independent (and/or weird) text wrap objects - draw a shape, set text wrap, lock it and forget - then just run text box over. Or the opposite - having a clear space around the object - draw a mad or exact shape you need around, group it and move around freely and it will keep the area around clear. Or as a little complicated spacer - draw a shape and lay and snap the other objects around. Or a simple spacer to help you arrange objects. Or when constructing and applying crazy layouts - even with sophisticated guides, grids and measures you can't do everything. Just draw a few boxes and shapes representing the layout and snap objects to them. Then pull some guides and delete them or keep them to copy and paste to transfer layout across different documents. Or sometimes we put empty or white boxes on the page, so in the workflow sw is not ignoring and skipping empty pages. ....
It's an even worse example considering that it is a text frame and you can turn on visible frames for those (Show Text Flow in the View menu).
No, that example is very accurate indeed. Also white filled objects are not visible.