Comment by Cogito

The primary reason for using detergent as a currency, beyond the fact that the market for stolen Tide is so strong, is that shoplifting carries a far lower penalty than robbery or burglary -theft-.

If they were robbing the stores at knife point, or breaking and entering, the risk is significantly higher. This way they have a low risk, easy to turn over, virtually untraceable scheme, and that is obviously a very attractive thing.