Is Autocomplete A Substitute For Spelling?

Not exactly: 

For one, you need to get somewhat close to a word’s proper spelling in order for it to be helpful. Second, it hasn’t yet been incorporated into most email and word-processing programs. The recent Google Docs upgrade is a significant improvement over traditional spell-check tools, but work remains to be done. Google Docs now flags the Brittany in “Brittany Griner Baylor” because that’s a popular search term. But when it comes to a phrase like “Brittany Griner of Baylor,” which you’d be more likely to use in an essay, Google Docs is mute. Spell-check programs will probably never make spelling as easy as a calculator makes arithmetic. But at least now they can put two and two together.