It probably is based purely on flavor. My nephew used to put sardines on his pb&j. No one told him to try it so we dont know ow where he got the idea lol. He was just some 6 or 8 year old kid eatin making shit up. Me though, I love tinned fish thats cleaned, but those are usually skinned and not fileted. The bones dont get in the way but it grosses me out too much when I see a spine, plus the occasional pin bones that I cant handle texture wise and annoyance. Even anchovy filets have some of those tiny bones. Yea you just chew up the whole thing but I cant do it. Love em broken up into some hot oil to flavor stuff though. Or the dried tiny strips Asian stores have that are good in/on stir fries especially when fried crispy