I totally agree. My Libre has been invaluable to me, but interim HbA1c tests would merely be curiosity and of no real benefit. Apart from anything else, I pay very little attention to my HbA1c because whilst they are a useful tool for diagnosing diabetes, I don't believe they are in any way useful for determining tight control. I'm in the variability school, and as long as my glucose deviation is good, and my finger pricking and libre give good results, I am happy. The HbA1c will never show anyone the sort of dangerous swings they may be having, it just shows the average of the highs and lows.
https://www.bd.com/us/diabetes/page.aspx?cat=7001&id=14131
It is also an unreliable marker for anyone whose red blood cells do not live for the standard 120 or so days - either short lived or long lived. And how do we know how long our red blood cells live? We don't without extremely expensive special tests. So basically, we don't know if our HbA1c results are actually too low or too high.