I'm wondering the reason behind syncing flight records? Also, if you delete flight records are they gone for good or can you get them somewhere?

If you sync them and delete from the app, resync to get them back.

RedHotPoker

There's no need to synch your records unless you want to share them with DJI for warranty or support.
Or you want to store them to be available when/if you change tablets etc.

Or you want to keep up with your flight time in a logbook.