Just to be the devil’s advocate here, autocomplete makes communication for people with disabilities much much easier. It takes people with disabilities three to five times as long to interact with a web based application such as email. Being able to use canned responses (i.e. selecting “Great Job” or “See you then”) instead of having to dictate it (and perhaps have to fix that), or laboriously type it out through some type of adaptive keyboard device really cuts off a lot of time in their required interactions. Also, typing for people with poor hand control is just plain physically and mentally tiring. Eye gaze keyboards require intense levels of focus, and frequent breaks have to be taken. Again, autocomplete will help alleviate that. I’m not saying it’s good for everything, but it definitely does have an advantage for this group.