NO one believes that the English system of measurements is better than the Metric System for non-base 10 numbers, do they?
An example:
The English system of 12 inches to the foot makes it easier to do division by 2, 3, 4, or 6 than the Metric system. These types of division are common in, among other professions, construction. Also, working with fractions, which is common in the English system but uncommon in the Metric (which tends to use decimal portions), is very useful in a number of "blue collar" occupations.
That's not to say these jobs cannot be done in either system, but some tasks *can* be easier in the English system. I have equal facility with both, and use whichever is more convenient, converting in my head when needed. I also commonly do math in different bases, converting between them, I use algebra and set theory on a daily basis at work (and calculus occasionally), etc.