mongodump replicaset - 10 hours data loss acceptable - do we need --oplog (oplog.bson) option? We have a 3 node replica set. We take backups from secondary with mongodump. Our customer said that it's ok too loose 10 hours of data in worst case.

So we decided we don't need point in time recovery --oplog (oplog.bson).

Is this correct in our use case with 10 hours of data loss acceptable?

Is oplog the same as MySQL binary logs?
Yes. OPlog is kind of the same as MySQL binary logs as both are used to sync data to secondary and point in time recovery.

You can use mongodump without --oplog option. You will only loose current writes in your backup. As you have a 10 hour window it wouldn't be an issue.

In this scenario I recommend you to use one of your replica set with slaveDelay.