* The one and only physical button car took 10 seconds total to complete their tasks
* Two touch-screen cars (Volvo C40 and Dacia Sandero) took only 13 seconds to complete the tasks
* Most touch-screen cars take 20-40 seconds
These results are certainly consistent with the hypothesis, "A moderately well-designed physical interface is likely to be better than an extremely well-designed touch-screen interface". But it's not really enough data to support the hypothesis that all physical interfaces are better than all touch-screen interfaces. You'd want to see what the curve looks like -- with it so close, it's quite possible that some, or even many, physical interfaces would take longer than 13 seconds for their benchmark.
And if you slow people down by 30% but reduce costs by a significant fraction, I think that's probably worth it.
* The one and only physical button car took 10 seconds total to complete their tasks
* Two touch-screen cars (Volvo C40 and Dacia Sandero) took only 13 seconds to complete the tasks
* Most touch-screen cars take 20-40 seconds
These results are certainly consistent with the hypothesis, "A moderately well-designed physical interface is likely to be better than an extremely well-designed touch-screen interface". But it's not really enough data to support the hypothesis that all physical interfaces are better than all touch-screen interfaces. You'd want to see what the curve looks like -- with it so close, it's quite possible that some, or even many, physical interfaces would take longer than 13 seconds for their benchmark.
And if you slow people down by 30% but reduce costs by a significant fraction, I think that's probably worth it.