Oh, yeah, I never use the Convert menu itself. I break down my gear from my Armory Inventory exclusively. See, if you right-click on your items, there's a whole list of things it shows - Try On, Meld, Desynth, Link and so forth. The "Convert" - if present (sometimes there's stuff you can't) - option will reduce that item to materia. That way you're looking at it in the inventory and can spot the page icon and make sure you're not destroying those.
Oh man, I never noticed that, what a waste!