it's a mild to moderate inconvenience on a phone, since you are looking at the screen most of the time you are using it and swype style keyboards remove most of the pain of typing on a virtual keyboard. it does make for a compromised music player, though, unless you can remap the hardware buttons to control media playback.
on the other hand, i find the touch UI trend in cars absolutely horrible. it's bad enough that you have to take your eyes off the road to read the center screen, but actually pressing a virtual button requires even more concentration to track where your finger is wrt the button and stabilize it against the motion of the vehicle.
It is basically a boring re-implementation of search, except that for many big companies it has the side effect of causing them to work harder to make their search actually work well. Even if the UI ends up being poor or temporary, the investments in better knowledge management and search ranking internally ends up being a net benefit.
Source: have seen behind the scenes at some larger outsourcers supporting these kinds of chatbots for customer service bots.
That basically sums up what I think of these things. They're a horrible substitute for existing UI, and even worse for things that really require a real human.