I also think that the "Close App" and "Delete App" are way too close and a few weeks ago while talking on the phone I made the mistake of deleting NBA 2k14 and had to re-download all 40 Gigs of it !
Mostly the only time I'll ever really close down an app is if I'm running Netflix whilst playing a game simultaneously in the background. When finished with Netflix I'll shut down the app and return to the game. Other times this could be if I'm jumping between two different games.
If you feel the need to close down what you're doing during standby then it's probably better you do if you feel like something's going to happen. No disruption of where I was in a game when entering standby mode has happened so far. But then again, I usually don't have the need to put the system into standby mode either.
I was under the impression that when you place the console in standby, that it closes the apps. At least, that is the way my PS4 works.
So, I never close apps, I usually keep Netflix open, and if I want to play a game, I short press the PS button, select the game, and play. If i want to go back to Netflix, I short press again, and select Netflix. You can go back and forth like that without ever losing your place in the game.
When I'm through with the console for the day, I place it in Standby Mode, and when I restart I always have to restart the apps.