Noone will think you're a snob! You're a snob only if you think yourself better than other people. Snobbery is judged by action and opinion, not how you choose to express yourself. Just because most snobs through history have used high language does not mean that that form of language itself is tainted in any way.
People will think you're interesting if you use thoughtful language and imagery, as there's nobody more gratifying than the person making an effort to be engaging and interesting when they're talking to you. There's so many people who talk exclusively in dressed down, dull language these days that it can be positively thrilling to meet someone who dives deep into the glory of the language.
And it will help your work. Most of the greats may have only been authors while at the manuscript, but they were artists all their lives, in all their correspondence and the artistic flourishes they put into everyday interaction. It helped them. If you actively dumb yourself down while away from the writing you are essentially entering a double life which can only lead to confusion and your work suffering. Many old writers have reams of fascinating correspondence that dwarf their oeuvre (somnetimes the letters are comparable to their best works, which is why collected letter collections are still so popular today), and was the source of many of their ideas.
It's surprisingly easy to improve your language. You don't have to bury yourself in a thesaurus to get good vocab skills. You can expand your vocabulary simply by forcing yourself to slow down and look for proper ways of saying things instead of just rattling your messages off. Not to come across Luddite, but I think the move towards using speed and shortcuts in our communications is quite damaging for culture. Read any personal handwritten letters which survive from the 18th/19th century, and it's amazing what an articulate and expressive style even the ordinary people possessed, not because they were cleverer than us but because their slow mode of communication meant they considered their words far more than us. Most of us have a way with words which we don't even know exists because it's never strictly necessary for it to be used. Indeed, the perception that using big words is somehow pretentious actively scares some people away from finding it, which is sad.
Most of the big words which we all know but are rarely used are not synonyms that every day language make obsolete by parsimony, (which I think is a popular misconception), they're vital to proper expression and every person who doesn't have them is missing out.
Also, it can be very useful to flex your linguistic muscles simply because single words themselves can be inspirational through their richness and evocation. Every single word you know is associated in your head with something different, maybe a memory of where you heard the word or a person the word evokes or even another word the word rhymes with, there are millions of possibilities and any can be a source of inspiration! Using your vocab thoroughly is great for helping original thought. The more words you have on your side, the more places your imagination can go. Every little one you win over is like a new recruit for your army, with their own special skills you can use. (Ooh, I did an imagery!
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Think I may have gone off on one of my own rants there and ignored your question a bit, sorry! Good luck with it anyway
