Write to disk has no practical latency because of write buffer, either local file system or remote database. Flush to disk would be slow unless you use SSD.
On the other hand, a single machine has limited reliability. If one wants to have high availability, they needs to dual write to another machine, which also has network latency.
On the other hand, a single machine has limited reliability. If one wants to have high availability, they needs to dual write to another machine, which also has network latency.