Why are IUPAC names necessary?

Believe it or not, it is easier to have IUPAC rules/names than to name all compounds after someone/something or to give them nick-names. It would be confusing.

Why is that?

Because there are so many compounds and we want to know everything about some compound just by reading its name.

Formic acid (also called methanoic acid ) is the simplest carboxylic acid. Acetic acid, sytematically named ethanoic acid.