It is in the name of efficency. All engines have a brake specific fuel consumption map, which plots how fast it uses fuel as a function of RPM and load (looks like a topo map). For the zetec in my focus, that is between 1500 and 3000rpm and 1/2 to 3/4 load. The more you can keep the engine in the zone of lowest consumption, the more effecency you squeeze out of it. More gears help to keep it there. The most ideal transmission for this is a CVT, but people seem to really dislike CVTs and in general do not buy them.
The other benefit would be only 1 rear end choice required with so many gears. I wonder if they are going to use some under/over inside the new transmissions to multiply the ratios
