I found this article and study interesting. It was done in England but I think it has plenty of relevance here. Even at the elementary school level some of these words, spelled right or wrong, occur quite often in the student's experience.
For the words above the k-5 vocabulary I don't think it's a bad idea to use this list as a way to make students aware of common erros through the spectrum, it might just help them become better spellers.
Is is the fault of spell-check so many common words are misspelt? Possibly. Should it matter that we have spell-check at our disposal? No, not in my opinion. Having a solid vocabulary should be a core tenet of any students education. Digital or otherwise, knowing how to spell correctly is a valuable skill.
20 Words you should make sure you know how to spell:
15. A lot
These are the 20 most misspelt words in the English language, according to a new British study.