e.g., drunks cause accidents
Especially in the context of customs and excise duties, this kind of imprecise but easy-to-use measurement is very useful, as you do not need a scale (or worse, lab analysis) to check if someone is carrying too much tobacco or alcohol
Understanding Cigarette Harm What Makes Them Dangerous
Haasova M, Warren FC, Ussher M, Janse van Rensburg K, Faulkner G, Cropley M, Byron-Daniel J, Everson-Hock ES, Oh H, Taylor AH (2014) The acute effects of physical activity on cigarette cravings: exploration of potential moderators, mediators and physical activity attributes using individual participant data (IPD) meta-analyses
(The Centers for Disease Control and Prevention reminds us that it might contain delicious arsenic, lead, and mercury.) But the public has a right to know