When integrating with some applications its useful to skip the "Get Data" call out page entirely. When this feature is enabled, advancing to the callout question will automatically launch into the external application (as if you'd pressed "Get Data" immediately). Further, upon successful return from the external application, you will automatically advance to the next question (as if you'd swiped right immediately). However, when data already exists for the question, you will not automatically launch (since presumably you might just want to resume and not overwrite the data). Further, if you cancel the external application and get no result, you will not automatically advance.
To enable this for yout question, find the odkx:intent definition block for your question and add appearance="quick". EG: