Multi Touch & User Identification through Touch screen?

The folks at report that MERL has created a touch screen sensor system that allows, and recognizes multiple simultaneous touches AND can identify who is touching the screen.

Seems like a pretty impressive technology. There is a 4.1M movie showing the sensor in action.

The question of usefulness comes to mind, and that is a two part question. If you can identify who is touching the screen, then what can you provide specific for that uses? When is multiple simultaneous touches useful. And is there more benefit if those two functions happen at the same time?

The article references games & automobile applications. Maybe there is something two knowing who is touching the screen in a car. Do you bring up passenger HVAC controls or driver HVAC controls? Games make sense too.

It seems to be based on capacitive touch technology, which may limit its use in certain environments like medical.

Where would you use this technology & how much extra would you pay for it?