I agree that executing fewer SQL queries is often better for performance.

However, it is possible that an elaborate SQL query that has to use many joins, correlated subqueries, and other operations can be harder for the SQL engine to optimize and execute quickly than a set of more straightforward queries.

Furthermore, these queries are simply hard to write, hard to modify, and hard to debug. I am hoping that these checks would serve as hints to developers to simplify and modularize complex SQL queries.