why do I need experience with database x, when I can pick it up in less than a week You can use a serious database like Postgres or SQL Server or Oracle for 5

why do I need experience with database x, when I can pick it up in less than a week You can use a serious database like Postgres or SQL Server or Oracle for 5 years or more and still not see more than a fraction of it or its surrounding ecosystem. MongoDB sure, you can know everything you need to know in a day.