Do some research on the topic.
There are some very significant differences between the two if you are looking at it from an engineering and performance perspective.
An AT uses a torque converter. AT's have gotten better, but its still a slushbox by design.
A clutchless manual will still have a disc and pressure plate, along with some mechanism (usually hydraulic) to engage/disengage.
In addition, some of the clutchless units have dual discs and shafts, allowing gear selection to be staged, with a net effect of *very* fast shifting, far faster then an AT. VW has this.
Its not just a technology for Ferrari, Porsche (PDK), and BMW (SMG): VW has had it for a few years now. You can get it on a TDI even. I think Nissan
only uses it in the US on the GTR, and that transmission is complicated by
the AWD system and other factors, it won't see duty in a Z ever.
It remains to be seen over time if this trend will increase or not: initially there is added complexity and engineering that goes into it. Early units were not as smooth in stop/go traffic as a AT but that is getting better with each generation. Some think a true manual is going the way of the dodo.
In the US, I tend to agree with that based on sales numbers and the number of people who utterly cannot drive out there.
In a perfect world, it would be mandated that every car has a manual (a few exceptions of course)...this would drastically cut down on the narcissists with their cell phones while driving. People would still do it, but it would be far less.
- b