There is a case to be made that teaching improves the understanding and insight of the teacher which in turn can increase their research ability. For starters, it provides a less boring way of drilling fundamentals. But more importantly, having to answer questions from students which very likely will be coming from odd and unexpected directions, helps the teacher clarify their thinking. It could well be that one of these odd questions, the answer for which the teacher takes for granted, may actually hold some insight or raise questions into what they are working on outside of class.

In a similar vein, it is recommended that if you are in a business meeting you hear what the junior positions have to say about something first and work your way up the chain of command rather than the other way around due to the junior positions being less familiar with internal processes and thus more likely to flag or suggest something completely out of left field that the higher ups might miss.