So that you don't have to setup all your alarms when you change your device or between multiple devices
Local backup
Create a zip file on your device that will contain all your alarm setups, your picture backgrounds and your preferences.
Online backup
Upload on Google Drive your alarm setups, your picture backgrounds and your preferences.
SAVE AFTER EACH EVENT - Enable this option to upload to Google Drive a backup after each event. An event can be an alarm creation, deletion, an alarm being enabled or disabled, an alarm skipped, dismissed, snoozed or missed, etc.
LIMIT TO WIFI - Enable this option to limit uploading to Google Drive only when your WIFI is connected and to save data.