Correct. Which means you still have to buy the phone when you get to the store, as supposed to just picking it up. Reserving the phone just gives you a chance to purchase one over the guy who just walk in and tried to buy having never reserved one. You still have to wait on line, you still have to set up your ATT info, you still have to deal with "first come first serve".
Why would the in app confirmation specifically say "Your product will be available until the end of the day"?