What are some reasons that the international system uses metric units and not the english system used in the united states?

Simplicity and usability

Explanation:

The primary reason for using the metric system is its simplicity

Converting one unit to another is very easy since they are all multiples of 10.

Ex: To convert meter into centimeter we just need to multiply it by 100.

To convert foot into inch, we need to multiply it by 12

The available range of units is one of the important features imperial system offer very few units. For example to measure length the English system offers few units like inch, foot, and mile where as the metric system has many units like centimeter, meter, kilometer, micrometer, nanometer etc

Also, it is used in most countries so it is has the international acceptance. It makes things easier for us when we travel abroad. We can understand the measurements used abroad.