Well it was just a toy example I came up with in a couple of minutes.

But sometimes depending on the requirements a file is enough. If you intimately know the and control the bytes that get written it is easier to understand and reason about your systems (that means optimizing it, scaling it, making it fault tolerant).

Also one way to make a resilient and fault tolerant database is to have less code running. Sometimes the base libc and unix offer a good and stable base on which it is easy to build. If you append the file in read or append only mode. You can rely on certain behavior now.

People in the past have bought into marketing crap and got stuff like MongoDB which would throw data over the fence and pray that it would be synced eventually (by default!). But heck it was WebScale(tm).