It's a very easy app to use. It involves taking your picture and putting in your passport biodata page details and a few other steps for actual use. Some of the additional steps have to be timed properly -- as in not more than say X hours before arrival or flight, and as in not doing the finalization process until on the ground using wifi network and doing so no more than two hours prior to presenting the receipt or something like that. [I don't have all the details on this -- as I haven't been into ATL yet using this app -- and I haven't had it looked at in extensive detail yet. I am saying I need check this out more or you need to do your own due diligence on it.]

This does have me wondering if/when this will mark the formal end of the no-phone/camera use policy/practices at CBP clearance facilities where this app is a means to facilitate CBP clearance of passengers.