Jee. Sus. Why? What benefit did anyone think that would have? Better than half the point of using SQL goes out the window if you can’t query across tables.
Wait until you have half a dozen teams or other services directly accessing your tables and now you need to update the schema or data container for scaling reasons, but you can't because they don't have the time to update their access patterns. Or the team that thoroughly misunderstood how the data was to be used and built their tables and workflows on your tables, forever linking their structure together. Far better to expose data through APIs if you have multiple teams doing their own things in different code bases.
