The argument about semi-auto gearboxes is silly. It is sole raison d'etre is enthusiast drivers, who want the convenience of an auto in traffic but the sense of control that a shifter gives.
I have a shiftable 5-speed auto, and I never use it. The auto does things just fine, no need for me to get involved. On long downhill slopes I may stick it in one gear to improve engine braking, but that is about it. I am just an average driver, but truth is, modern auto boxes are so darn good, they do a better job than I do.
For all the other average drivers like me, my conservative estimation is 95% of the public, semi-autos have absolutely no value.