Well… if it is the best word for what you’re trying to express, then don’t stop using just because it’s an uncommon or mostly unknown word.
The best way you and your readers can learn new words is by actually using them. If everybody wants to write with words that all their readers will know, we’ll end with a bunch of languages with 300 words each.
And, by the way, exsanguinate is a pretty simple word… it looks long, but its meaning is clear.