“One day I will find the right words, and they will be simple.” ― Jack Kerouac
More people will understand your message if you use simple words. Whereas, more people will have difficulty understanding your message if you use complex words.
If your main concern is to get your work out to the general public, then it's better to use simple words.
Human beings have evolved to be able to communicate with each other. If you can explain what you want with any type of word, that's fine. The words don't need to be complicated or hard.
What matters most is the message you're trying to communicate to the world; not complex words.
If I can jump in certain pattern and make you understand what I mean, then that's enough.
If I can make you understand my feelings by writing, "swauhidbthkbxeutkxugoedudalost" and you understand it, then that's done!
Using complicated words will only make your message hard to decipher. Which is of no use. Use words which everybody is familiar with.
If your target audience is familiar with complex words, then it doesn't matter. For example: Doctors, Scholars, Scientists, etc. But those -- hard to understand -- words should be avoided while writing for the general public.
I have been trying to make my writing as simple as possible. If I can communicate in simple words, then I've done my job well.
Explaining your feelings in simple words is really difficult. If you were to explain what jealousy means to a kid who doesn't understand the word, you'll have hard time explaining it.
“If you can't explain it to a six year old, you don't understand it yourself.” ― Albert Einstein
Simplicity is difficult, not only in words, but in every aspect of life. I have difficulty trying to make a simple website. Anyone can code a website that looks complex. But it takes lots of effort to bring it down to usability and simplicity.
Simple websites are easy to use, easy to understand, nice to look at. In practice, websites are either unusable or ugly and in general filled with too many complicated words.
Simplicity is the most difficult thing to secure in this world; it is the last limit of experience and the last effort of genius. - George Sand
Hence, try and move towards simplicity in every aspect of your life. Simplicity as a result of a creative process is “the ultimate sophistication”!