This has started to really irritate me since it feels like every application in Apple's mobile ecosystem does this. My device has SIX GIGABYTES OF MEMORY[0]. Why do you need to swap everything out of RAM almost instantaneously?
What grinds my gears the most is that state isn't preserved. Apple Maps and Music are the absolute worst for this. Music will show the same screenshot and then just unceremoniously dump me to the "Listen Now" or "Browse" screen (it seems random which) and completely disregard whatever playlist or album I was in. The last song I played and track position are kept but good damn luck getting back to the spot I was in--particularly which playlist--before the app got put on ice.
That screenshot is just a point of "hahaha nope" frustration.
0 - Yes, I mean actual Random Access Memory, not "storage capacity."
A screenshot of the app shouldn't be a loading screen!! It seems to depend on how long it's been since the app was last opened and/or how the internet connection is at the time. Bank apps show a proper loading screen.