Not sure if it is cheaper but according to the founder (paraphrasing from a podcast he was on in Iceland)
The pig skin has possible viruses that can infect the human body, so they need to dip it into an acid to kill any potential infection, this destroys the pig skin. With cod living in different temperature, they don't have these viruses so they only need to dip into salt water to "clean" it, the cod skin keeps intact and therefore works better
The human body accepts the cod skin as normal skin since it's basically same at molecular level, because of evolution
The pig skin has possible viruses that can infect the human body, so they need to dip it into an acid to kill any potential infection, this destroys the pig skin. With cod living in different temperature, they don't have these viruses so they only need to dip into salt water to "clean" it, the cod skin keeps intact and therefore works better
The human body accepts the cod skin as normal skin since it's basically same at molecular level, because of evolution
Fascinating