There aren’t too many things more immediately and absolutely damning to one’s credibility than misspellings in their otherwise perfect text. When my seniors hypothetically ask me how to spell remedial words, I hypothetically feel pretty embarrassed for them.
Nitpicky? Sure, they’d certainly say so. But while it might be demanding for such folk, perfect spelling and grammar are esoteric goals all communicators (which means nearly everyone) need to strive for.