Red herring alert. Do biscuits and gravy have any history in the legal tradition of the Southern community? No, they do not.
First you were talking about using laws to preserve "regional traditions". Now you are changing to wanting to preserve "legal traditions" for the sake of themselves.
Okay, let's play your new game. How about that "legal tradition of the Southern community" known as Jim Crow? Should those cultural artifacts of legally enshrined prejudice have been preserved as well?
Blue laws are nothing more than discriminatory laws aimed at the non-Christian or non-faithful minority to enforce cultural compliance to the majority religious mores, using the power of the State. If an action is moral on Monday, it is moral on Sunday.