Intelligence becomes useful when it improves decisions rather than vocabulary.

Intelligence that only produces better vocabulary and sharper arguments has not been converted into anything. The test is whether it improves the decisions you make: about money, work, people, time. Plenty of very clever people make consistently poor decisions, and the cleverness is often what allows them to justify the decisions afterwards.

Look at your last few significant choices and ask whether your intelligence was used to decide well or to defend what you wanted. That is an uncomfortable question with a useful answer. The correction is to do the reasoning before the preference rather than after it.