Touchscreens are also far more suseptible to accidental button presses.
However, I bet the Nagra implementation is well thought out with all critical transport functions implemented via their standard rotating switch (now an electrical switch, but the design is held over from the era of mechanical transport controls), a design which is less suseptible to accidental switching than even hardware buttons.
Other manufacturers racing to add touchscreen functionality to their products concerns me more than Nagra's implementation. I can see the value of touchscreens for easier access to information screens and perhaps control of non-critical settings while recording, but no tranport functions please.