There are a lot of use cases where you only truly need consistency, and durability can take a back seat. RocksDB for example does not fsync its WAL writes in the default configuration.
If you can't at least guarantee write ordering you don't even have consistency.
Fsync is often used when the data doesn't truly need to be on disk, because there aren't very good write ordering APIs exposed, even if that's all you truly need.
Fsync is often used when the data doesn't truly need to be on disk, because there aren't very good write ordering APIs exposed, even if that's all you truly need.