There is a third way:
Be pedantic about your vocabulary in the right way to make your paper more readable.
Using established, clear, and consistent vocabulary and defining it when necessary is the best way to ensure that you are not misunderstood. The main advantage of “simple and easy words” is that they do not need to be explained to the reader, but this also entails that you rely on the reader interpreting these words the same way as you do, which may be not given surprisingly often. Defined vocabulary does not have this disadvantage.
Moreover, you need to at least need to mention the established, “pedantic” vocabulary for context and to avoid the impression of reinventing the wheel. By consistently sticking to it, you avoid switching between different terms for the same thing, which usually impedes intelligibility.
However, you should also bear in mind that readers unfamiliar with this vocabulary may want to read your paper. For these readers, define the more uncommon words and cite papers explaining the basic underlying concepts. Papers are not difficult to read because they contain new words, but because these words are not properly explained or because the reader does not understand the concepts represented by them. For example if you write a paper on theoretical particle physics, readers will have to understand some elementary aspects of quantum theory to follow your thoughts. Using vocabulary that can only appeal to readers without this basic understanding of quantum theory is pointless and only raises false expectations.
Finally, if you get to introduce new concepts, you can try to choose words for them appeal to intuition, but this does not mean that you are relieved from the burden of explaining these words.