I understand all that but I'm afraid I'm still not wholly satisfied. If the iPad is certified as an EFB why can I not use my iPad on the same aircraft that is using an iPad based EFB?
Now, again, I accept that from the point of view of cabin crew it would be almost impossible to say to me, using an iPad "yes" and my neighbour with an iPhone "no". So, I'm not asking the question from the practical point of view but more as a point of principle (and no, I won't be standing on my high horse somewhere demanding to use the iPad I don't own).