Answer:
The purpose of a theme statement is for the reader to know the gist or plot of the whole article/context. It gives the reader a much more whole and complete outline of the text, and it is much more beneficial than just using vague words, phrases, and other unnecessary context.
If you use words and phrases that are hard for the reader or person to understand, then there is a high probability of the reader not knowing what your description or summary of the book or context your reading. It is important to have the reader know the gist of the context rather than having a short snippet or sample of the text you are describing.
For example, you’re telling a person what Adventure time is about, “Adventure time is about a boy and his shape shifting dog jake that go on adventures in OOO, the name of the territory they live in that is a Monarchy ruled over by a princess.” Or something like that.