To be honest I thought more along the lines of basic human rights, like freedom of speech, going unharmed, making your own decisions, right to own stuff etc.
Nothing like those absurdities that get you sued because you didn't put a warning label on hot coffee....
All those laws SHOULD be extensions and clarifications of the former, but some are simply absurdities or invert the law because they were created to benefit somebody specific.
And yes, I firmly believe that they only exist to smoothen a lot of humans basically living on top of each other. It is such a hassle when you DO need to file a lawsuit, now imagine it if those rules were unwritten and you had to enforce them with a fistfight.
Regarding the "could benefit us" part - yes they definitely could.
So can quite a lot of animals, but they are still perched up and strictly under control. Even in those "bio-ecological" farms were they can "run free" it only means that the cage is bigger.
We think we should treat them well because they are still living beings and we know that they can experience pain and suffering, and our empathy drives us to avoid causing them such if possible (or most of us anyway).
But we still don't let the pigs decide that they don't want to be slaughtered, or the cows that they don't want to be milked and bred.
I'm pretty sure the pigs and chicken would prefer not to be slaughtered.
I wouldn't mind giving them a similar status, some laws that demand to treat them reasonably well (And if its only to avoid some nutjob "accidentally" cracking a real humans skull).
But let them run free and decide for themselves?
Nietzsche said we, HIS creations, killed god. I'd rather avoid the same fate.