Here's when a quick bracket/quote pairing check on a MySQL query actually saves you time in practice.
Deeper subquery nesting means more room for error
The more subqueries stack up inside a WHERE clause, the harder it gets to keep brackets balanced. A quick pairing check before running the query rules out one common cause of a "You have an error in your SQL syntax" error.
Debugging a query built dynamically in code
When application code concatenates strings to build a query dynamically, it's easy for a quote or bracket to go missing on just one branch of a conditional. Pasting in the final assembled query string and running a pairing check narrows this down fast.
Passing the check doesn't mean the query will run
Balanced brackets and quotes don't rule out a typo'd table or column name, or a broken join condition. This check is strictly a first-pass filter.