This is the killer feature of this, I am programmed for keyboard shortcuts, its why I'm productive in Vim, its why I use Gnome-do for launching, and its why I feel the web browser is my only real need for a mouse (Vimperator and the like don't seem to do it for me)
Once I hardwire a combination into my head, anything else feels slow and laboured to the point that I hate using it, and often I am found trying to use shortcut keys when a simple mouse touch would work better.
Some people are predominantly mouse people, and if they are productive doing this, this is of course ok, but a feature like this would be an added boon in my opinion for any website.