I have heard that the initial dock & go system took a serious battery bank to work properly. I would hope that issue has been straightened out since they are equipping more & more models with the system.
On my 2008 B46 I can't see a reason for it. The boat has a bow thruster & backs very true. Unless the current is a killer I back into my slip just using the prop walk to my advantage and don't bother with the thruster.