It’s something of a compromise. While your battery life improves, apps won’t update in the background if you’ve turned off background app updates. This means that the updates your apps normally do in the background, whether it’s sports scores, stock prices or the latest temperature, aren’t updated until you open the appropriate app and app updates. In other words, when you open your sports app, you may not see the latest score right away.
If you think your apps don’t need to be updated in the background, or you don’t care if your full screen effects play automatically in the Messages app, you might want to see if you can improve the battery life of your iPhone significantly by using these Deactivate functions.