Low level has it's place
Watch from about 17:10 for some low level Blenhiem action!
I guess its a case of a few bombers by themselves can't win a war, but using team work and precision techniques they can sure meet their objectives and roll a map.
Low level attacks aren't all beer and skittles by the way. They are quite dangerous and practically impossible to get away with if the other side can be bothers to protect their assets!