Well, I don't eat it, but I bought both black pudding and haggis today. My husband likes both. It's considered good food in the UK.
Black pudding is a favourite part of breakfast for many, and haggis is a meal in itself really. I know folks who take both a real haggis and a vegetarian (surprisingly good and tasty) too when they are camping; makes it a simple meat and veg dinner
Black pudding is blood pudding, and haggis is made from the 'lights' of the animal, the lungs, heart and liver, and any spare bits that could me easily minced up that would cook quickly when tied into the stomach and boiled. Classic medieval one pot cookery, but might well be a lot older. A stomach bag, or the intestines washed and stuffed full of finely prepared meat (that's sausages!) is easy to cook.
Mechanically recovered meat is commonplace in the food chain, though a bit less so in the UK since the advent of the BSE crisis. Funnily enough ours played out in full public scrutiny, other countries quietly kept their heads down
When my stomach ulcerated (anti RA tablets did a hellish number on my digestive system :/ thankfully all healed
) the gastroenterologist made comment that I'd be fine even if I did need antacids lifelong, since I was vegetarian. Stomach acid helps break down meat, kills pathogens, etc., but most meat still ends up just feeding the gut bacteria since people don't fully digest it, and it was unlikely therefore to cause me any issues since I didn't eat it anyway.
M