This is Grell's most dangerous experiment yet, so he's relying on the wisdom of the ancient Byzantine engineers.
So, you know these are basically better than the CIPT duals, right? They can tap to pay for themselves. Also, by being both land types instead of just having an ability to tap for the relevant colors, they also give you all the benefits of having played two basic lands as far as triggers and counting.Basically, these are significantly better than a wide variety of already playable dual land options. I'm intrigued, but ultimately think they need fixing.
Empty your mind.