It seemed like a silly idea at first, but since the air charge comes first and [u]then[/] the power it might be a slight improvement for small displacement engines in stop-n-go conditions.
Another benefit might be a faster restart for hybrids.
Remember the "self-powered turbocharger" turned into a turbine.
http://www.gizmag.com/electric-supercharger-promises-instant-power-boost/9364/2/
"For small engines to be effective in urban environments, they need near instant full torque availability for the driver demanding strong acceleration. Such responsiveness is essential to avoid fuel being unnecessarily wasted because the driver must continually select low ratio gears in order to keep up with traffic flow."