Pound

Origin:
The unit is descended from the Roman libra (hence the abbreviation lb); the name pound is a Germanic adaptation of the Latin phrase libra pondo 'a pound weight'
Relation to SI unit:
SI unit for mass is kilogram. One pound is equal to 0.45359237 kilograms which is equivalent to 453.59237 grams.
Disadvantages over other units:
To me, I find that using kilogram would be easier to use compared to pound. The pound has too much decimal place so it would be difficult to use pound. It would be hard to be exact because if an object weighs 1.5kg, you will have a hard time calculating to find out the exact amount which is 3.306933933 pound.