Yes that's the big question, and I mention that in the article. Let's say for a moment that we can't achieve 100% accuracy, well one parallel to this situation would be autocorrect on our phones; it often corrects you when you didn't want it to or misinterprets your meaning. Yet we still use it as there is net gain in terms of convenience. If a BCI could instantly put your thought on to paper, and left you solely with a few typos to mop up, I think we'd all be willing to compromise.