Because some people eat salmon more than once a month, care about the environment or animal welfare, and don't think that processed foods are inherently disgusting.

Yeah, I'm personally very bullish on processed and ultra-processed food. If we make it that far as a race, I suspect in 100 years from now we'll be eating a more processed diet and it will be more healthful than our current diet.

Mix in the benefits you mentioned and it seems like a no-brainer to me.