> As implemented, you’ll now need to implement a ton of custom logic for the necessary data transforms. With Postgres, there’s a really good chance you could do all of that by manipulating the backups with a few lines of SQL.

Isn’t writing «a few Lines of SQL» also custom logic? The difference is just the language.

It is also possible that the custom data store is more easily manipulated with other languages than SQL.

SQL really is great for manipulating data, but not all relational databases are easy to work with.