@Kilisi Where I live, it's pretty easy to find canned tomato sauce (I have some). So it doesn't seem like we are missing out on anything. I can't imagine using canned tomatoes as a condiment or spread on bread though. (shrug)
@JoeStrazzere great. Unsure what else you would use it for than a condiment. But so long as you're not stuck with the sour stuff. I had some penniless times in my youth, so spread it on everything from pancakes to wheetbix.
@Kilisi I occasionally use tomato sauce in recipes: meatloaf, spaghetti sauce, barbeque sauce, stews, etc. I've never tasted a ketchup that I would consider "sour". All of them here are rather "sweet". Perhaps whatever you tasted was spoiled?