I think it's helpful for engineering managers to be technically conversant at a fairly deep level with the technical challenges and domains the team deals with regularly. My reports have told me that in the past, this bolstered their trust in my decision-making and gave me deeper credibility overall.
I didn't do anything terribly difficult/deep, but I think it conveyed a strong, empathetic connection to what they were dealing with that mattered to them.
I agree! All managers should have been mid/strong engineers at some point, and have developed stronger soft skills to become a leader. Without the technical knowledge and understanding of the processes one can't have the needed credibility and trust for other engineers.
I didn't do anything terribly difficult/deep, but I think it conveyed a strong, empathetic connection to what they were dealing with that mattered to them.