If you log in to iNaturalist via Seek, you’ll see this notice:
Observations are saved only in Seek unless they are posted to iNat. But note that observations on iNat can’t be synced back to Seek, it’s a one-way connection.
If you have an iPhone that you back up, you can restore your Seek observations from that backup if you need to, which I had to do last week after my phone sailed out of my pocket into San Francisco Bay as I tried to get a sweet bird shot. I’m not sure that’s possible with Android backups.