You actually can try it out in incognito mode and any other browser. But we found that without the convenience of a navbar search, most people won't give it a proper try either way.
I hope we can drop this requirement even in Chrome when we become one of the default options.
If you set your search engine default to http://you.com manually in Chrome with "https://you.com/search?q=%s" you will not need the extension... but for most people convenience wins and well...
It's tough to go up against a monopoly that controls the browser too?