Fractions have real use and the metric system has nothing to compare.
What does this mean?
It means you are missing the point. Tell me what metric dimension equals a gallon? then divide it into 4 equal parts. What does that look like to you? Tell me what metric dimension equals an inch, put it on a steel tape on a metric scale, divide it into 4 parts and tell me just how easy this would be to follow on a ladder 20 feet up calling out numbers to the saw man.
