Why is it important that scientists use common units of measurement?

So that it is relative in comparison to other scientists for example, if people in the us used Canadian money, Mexican money, and Australian money, it would be hard to keep track of how much it was worth in comparison to each other bc the Australian money can be worth more/less so it's easier to stick with 1 form

In this sentence, hard is the adverb because it is modifying the verb.