Hi Daniel - The critique is welcome, but here is my rebuttal:
The "white battery pack deal" contains all of the electronics - bluetooth transciever, antenna, timing crystal, etc. There is also a small watch battery inside for power. All in all, it is really small and surprisingly light (less than 1 ounce).
The reason for the cable is twofold:
1. There are two ways to trigger the shutter on most cameras: via USB, or via shutter release port. USB has issues with lag, power consumption, and manufacturer specific protocols. This is why the BlueSlr you linked to is Nikon only. The Shutterbug uses the shutter release port, which is a standard protocol and can even be found on older cameras without USB options. It is designed to simply extend your shutter button to a different location.
2. By using the shutter release port as mentioned above, one has to deal with the fact that every manufacturer uses proprietary connectors. Instead of selling a Nikon Shutterbug, a Canon Shutterbug, an Olympus Shutterbug, etc. we chose to make one Shutterbug unit with cables that connect to any manufacturer.
As for your hope that in the near future, the manufacturers will put bluetooth into the cameras, I do believe it will be the case. Unfortunately, most of us have invested heavily into our equipment and, at least for me, it will be a long time before I am upgrading camera bodies.
Hope that addresses some concerns.