I have uploaded a post on the advantage of hand key or bug key as a bait to get a call for CQ several days ago. The idea of bait was given by Bob W6CYX. He often just listen to me calling CQ with an electronic keyer again and again. When I have no calls, I try a hand key or a bug key for a change. Then he gives me a call telling that he has eaten a nice bait.
It has been a matter of consideration for me what attracts good CW operators like Bob to hand key or bug key. It may be related with the fluctuation of the keying by those keys. Our life, itself, fluctuates. Heart beat, breathing pattern, consciousness level and so forth. This fluctuation helps us to accustome to the environment. Without it, we might have much difficulty to get along in the ever lasting changeable environment.
Maybe, we feel comfortable when we see or experience anything fluctuating. Keying may not be an exception of such a thing. Keyboard keying, even though so neat and clear, won't fascinate us so much. It sounds like a march of military in a sense. Too rigid and breathless. On the other hand, hand key or bug key sounds like breathing in free air. It assures us freedom. It is so characteristic that we feel as if talking to someone in face.
This idea is just an idea. Not any scientific fact at all. But it is a fact that we are attracted by hand key or bug key.