Yes, it was part of our staple diet during World War II. As I understand it, this was a product that "grew" out of the Food Rationing situation. The food resource had to be managed carefully and as efficiently as possible. A bit like sausages.... chop up every bit of the animal, even the less-attractive parts, then combine everything into a palatable mass. Cook it in the most tasty way, add some kind of cheap sauce, and you have a good meal. This was the to make the resources "go round," when resources were meager.
I agree with those folk who loved it during childhood. Spam dipped in batter, then fried in lard, or dripping, served hot, with tomato ketchup and a slice of bread and margarine (we only got a ration of 2 oz butter per person per week...) and that was our "tea," served around 5 o'clock in the afternoon.
Tinned, dried egg was another part of our Ration diet. Does anyone remember that?