It's not like that's the only choice. They could have local auto complete and only send the search request to google when you hit enter.
... and that's what it used to do IIRC.
Today you'll also have to turn off "Show search suggestions in address bar results" to get back to that behaviour it seems.
It's not like that's the only choice. They could have local auto complete and only send the search request to google when you hit enter.