User blog comment:Viperys/Konosuba Crack Theory (careful, spoilers)/@comment-29694966-20161112010821

The process to send Aqua away to Konosuba world was indeed very fast and efficient. I think there might be three possible explanations:

1. Heaven just works very efficiently: That angel is already trained at different parallel world(s), so she can just quickly show up to process Kazuma selection of Aqua as his divine relic.

2. Someone really want to send Aqua to Konosuba world: Her numerous antics aside, Aqua is an useful and powerful healer. (Although she sometimes stayed out the harms way, let the people die, and resurrect them after it is safe to do so.)  Sending her to Konosuba will provide great help to the people in there ... and give some peace and quiet to heaven.

Aqua may have also ticked off some higher-up gods. Remember. She bad-mouth heaven, saying how boring it is, to dissuade people from choosing the heaven route.

3. It is not the first time someone selected a goddess as divine relic: Selecting Goddess may have happened before, so they are well prepared this time. (I wonder about Wolbach's backstory., which the author foreshadowed, but did not reveal.)

I think the real reason is likely a mix of all three.