Why was redundancy trade, e.g., trading corn for corn and meat for meat, an important part of the Plains trading system?

yo mama so fat when she walked in front of the tv i missed 3 episodes of family guy

yo mama so fat when she wears a yellow raincoat, people yell "Taxi!"

you mama so fat when she wants to take a bath she has to go to seaworld

Ms. Sue can you please help me

Yes.

get outta here wit dat mess

yo mama so stupid she got hit by a car

Yo mama's so fat when I pictured her in my head she broke my neck.

yo mama so old she sat next to jesus in the third grade

yo mama so stupid she sold her car for gas money