You might be thinking "What is the point of a 64-bit browser?" Performance of course! Google states that there is about a 25% improvement in performance and crash rates for the renderer process are almost half that of the 32-bit Chrome.
"The new version replaces the existing version while preserving all your settings and bookmarks, so there's no need to uninstall a current installation of Chrome. The majority of our users on Windows 7 or higher now have systems capable of running 64-bit applications, and this version of Chrome can take full advantage of these newer capabilities. This includes several improvements that align perfectly with Chrome's core principles of speed, security and stability"
Of course being a 64-bit application requires a 64-bit operating system to run it so it is limited to Windows 7 or greater. However, if you really want the low down ask a Linux user because the 64-bit version of Chrome has been available to them since 2009.
If you are still sceptical you can try it out for yourself here and if you do don't forget to let us know what you think.