DVD-R media with "capacity windows"

DVD-R hasn't really seen a lot of action these days, especially now that virtually all new recorders support writing Dual Layer discs. Doing so is still cost prohibitive, but DVD-R DL writers are up to what, 8x now? It would seem there really isn't a lot of room for innovation left in the recordable DVD world. But here comes Ricoh, announcing their new line of DVD-R media that includes a "remaining capacity display window" in each product package. You put the disc inside of a sleeve, look at the recording surface of the disc, and a little chart will tell you how much recording time you have left on your discs. And you're telling me nobody thought of this earlier? Sure, an experienced disc burner can tell by just looking at the disc's recording surface (protip: the recorded portion will appear lighter than the unrecorded portion), but not all of us are so gifted.