If I remember correctly, the bands are only for the rooms and the cards are for the parks/WWOS. You can't do it in advance like you can for a normal family vacation. If you go to Disney on your own, your band is everything. At nationals we get bands and traditional plastic credit card type passes. I think it's because our park passes are different then a normal Disney park hopper, but I'm not really sure why they do it this way. The kids seem to have a hard enough time keeping up with one thing, now they have two!
Last year we had an app on our phone, my Disney Experience maybe? I think we tied the barcode on our plastic park passes into the app. From the app we were able to set up fast passes. What I do remember is that your pass can only be tied to one phone. So if you put a group of passes in your phone, and then one person decides to go to another group, it makes it challenging for fast passes. I think we did finally figure out how to remove a pass from a phone.
I could be mis-remembering and have this all wrong. I go to Disney a lot, so I tend to forget how they do things at nationals. I just remember I never think it makes much sense... not to mention I think it's been a little different every year we go!