The impression I get is that the App holds all the Data about events & "My Schedule" within the Apps phone memory, and does not rely on having to make an Internet connection to view events or change "My Schedule".
(maybe it can update it's event lists etc, but does not need a connection to function and display what it already has)
This would appear to be a BIG advantage over the Web Based Scheduling, as getting a reliable connection to the Internet or for Cell Data might be difficult at times at the event. (Those local cell tower must be highly loaded during the Oshkosh week !!)
I like it all being self contained on the Phone App , much easier/convenient to use than a web based solution.