I'm not rotary, and my Engineering has far more to do with analysis and approval than building and fixing, but speaking as both the more flying I do the better an Engineer I get, and the more Engineering I do on the class of aircraft I fly, the more (as a pilot) I'm able to be "on-top" of what the aircraft is doing.
But, it must be said, there are some incredibly competent Engineers and Technicians who never fly, and some very able pilots who haven't much of a clue as to how their aircraft work - it would be arrogant to say that it's universal.
G