Possible reasons: metric system is used by scientists and all over the world. It is easier to use and creates simpler calculations.
Work Step by Step
There are many good arguments for why the US should switch to a metric system. Primarily, the metric system is very useful for science. Units exist in denominations of 10, rather than arbitrary values, fractions, etc. The metric system is used all over the world and switching to a metric system would make international relations easier (for example importing/exporting goods, travel, etc).