Why is the metric system easier to use than the English system?

Easier to use is an opinion.

The metric system is used in science because to share data with less conversions required (ergo, more easily) with all other countries in the world (who the majority of) it was easiest for everyone to agree and use the metric system.

Then collaboration and potentially (hopefully) the advancement of science and, with that, the cure (s) for disease will happen more quickly.