If you're not logged in, as I'm sure FSF people are, then this is a much bigger deal, but it doesn't apply to the vast majority of people.
All that said, the keylogger would take a good deal of interpretation to get a complete or even partial history, since autocomplete choices would likely be chosen anyways, not fully typed out URL's. If they send that history anyways on any time you press enter, the autocomplete feature again doesn't matter because they have it with our with.
Also, your aggregate value argument is quite apt: It's valuable to know what percentage of a city speaks English, but the fact that you personally do or don't is of no real value at all, specifically because it's "your" individual data, not despite the fact. And insisting that you've been hypothetically robbed of your entitled half penny for disclosing your language preference to the McDonalds cashier is precisely as sensible as complaining about the value of your half-typed URLs.
At the end of the day, serverside autocomplete is useful, and coal is cheap!