Why are roman numerals important?

Answer 1

You'll see a lot of Roman Numerals in Chemistry. When naming compounds, you'll need to know the difference between Iron (IV) Carbonate and Iron (II) Carbonate, for example.

In plays, often acts and scenes are organized with Roman Numerals. (Act III, Scene I).

And, in all honesty, lots of people will use Roman Numerals just to make something look fancier. Its typically a good idea to know at least the first five roman numerals off the top of your head.