One spelling mistake that touched my funny button was the misspelling of the word: Rankle. it was spelt wrankle. It took a second or two to realise what was actually meant.
I once managed to fit 303 spelling mistakes into thirty small A5 pages of text, albeit aged ten years, (with plenty of illustrations in the booklet called "Smugglers bay"!), so I should be some kind of expert on this thread topic shouldn't I hey!
Nope. No more than the ability (or inability) to spell is a sign of intelligence (or lack thereof). Not to worry. I can spell and punctuate and construct compound sentences. I can't cipher to save my life except by twos and tens.
I gotta admit I like "spenditure". It really fits. I'm dyslexic, so spelling isn't my strong suit. We have all kinds of spelling rules, and I manage to use the words that don't apply to them.