The link i gave you arent the same, so i dont understand where i posted it "twice".
One pdf shows you all the mia_material output passes available so you start to learn them visually.
The other is a link i've found that shows some random compositing.
The third link from simon reeves is just a normal compositing example.
Now to me it seems you are a little confused on compositing in general.
If to you it seems a waste of time to export ID passes or passes in general its because you dont need to do so. Or because you dont need to compose images.
The fact that there are passes doesnt mean that you always have to use them. When it makes sense to use you have them available.
I told you that ID passes are mainingly used as masks, and you consider this a waste of time.
Ok lets say you have an architectural render of a skycraper with 180 windows. Now you look at the render and you dont like how you rendered the transparency or glass of those windows, what do you do? re render everything?
Here you could just export an object ID pass where all your window have a constant color (saving your time to go and select them in photoshop manually). You open photoshop give the render layer this mask and voilà, you can use any effect you want in this particular area using the object ID pass on those windows.
This is the basic of photoshop, masks. How is it a waste of time?
Also you didnt apply enough into googling stuff because there are a lot of things regarding compositing and postwork.
here is one for example
www.ronenbekerman.com/photoshop-postwork-the-shipyard-breakdown/As you can see the first is the raw render he ouptut from the 3d software, and after there is the final shot composited in photoshop. Guess what he used to isolate the elements and customized them in photoshop? Yep the ID Passes.
www.cgdigest.com/vray-render-elements/www.vfxcommunity.com/index.php?topic=359.0www.cgsource.net/render-passes--compositing.htmlwww.google.com/search?sugexp=chrome,mod=19&sourceid=chrome&ie=UTF-8&q=how+to+composite+raw+passes#hl...www.pixelcg.com/blog/?p=98www.fxfx.org/index.php/2010/02/05/how-to-render-object-id-pass-and-use-it-in-after-effects/www.google.com/search?sugexp=chrome,mod=19&sourceid=chrome&ie=UTF-8&q=how+to+composite+raw+passes#hl...Seriously you dont know how to use google?