For those who answered 'I write plenty fast, so I don't need an autocompleter':
The question is not whether you need it, but whether it brings any advantage at all. So if you hear someone saying "we don't need an autocompleter," that use of the word "need" is a sign they're not even thinking about the question right.
If you 'write plenty fast', it takes very little thinking to realize that writing faster is better.
So that option shouldn't be there: it reflects a misconception.
Imagine that you are in business. And you found a area where you can invest (say google adwords) that costs you say $1 per click, but makes you $1.1 in profits.
If you find something like that -rare-, it takes a special kind of stupid to put a cap to it, and limit the amount of money you allocate to it. But in fact, this is what many people in business do!
Is this metaphor clear? It must be shocking to realize this...