In the 130J community we have moving maps for JOGs and such. Mostly used for tac. For other flying, it's a great SA builder because we can overlay our position and our flight plan. I'd imagine the iPad moving map would be similar. Mostly just an SA builder, and a way to keep organized.
As for your frequency dilemma, I'd imaging that we would be backing up our iPad for a while. Similar to how we still back up GPS with ground based nav-aids. (Is that still done in most communities? Our GPS isn't certified so we have to back it up to be legal).