I believe you can sign up an account for free or incredibly cheap ($5/user). You would potentially have tens of thousands of databases. Imagine trying to do som

I believe you can sign up an account for free or incredibly cheap ($5/user). You would potentially have tens of thousands of databases. Imagine trying to do something like a database migration to add a column. I believe the day to day operations would be a nightmare as no RDBMS has probably had that kind of feature stress tested.