One of the mental frameworks that convinced me is how much of a "free action" it is. Have the LLM (or the agent) churn on some problem and do something else. Come back and review the result. If you had to put significant effort into each query, I agree it wouldn't be worth it, but you can just type something into the textbox and wait.

Are you counting the time/effort to evaluate the accuracy and relevance of an LLM left to "think" for a while?