I think the concept of the wallet that can quickly snap on and off of the phone is pretty neat. I currently use a case that has a wallet functionality (for my driver's license and credit cards) and that doesn't allow me to use wireless charging without completely taking the case off.
I suspect the magnet will make it a sure shot thing with the new iPhone though. With current phones you can often get away with keeping a hotel card in the same pocket as the phone.
For NFC, the NFC antenna on an iPhone is on the top rather than the back, so as long as you only have one NFC credit card in the wallet on the back and then presumably it will work based on if you tap the top or the back of the iPhone to the reader
PopSocket has already confirmed they're working on something. This will be awesome for those of us who don't use wireless charging because of our popsockets.