For those boxes, 'digital' is just implementation detail. User interface and interface towards other equipment is still completely analog. I agree that they look very clean and usable.

I don't think there's anything wrong with displays. They offer immediate and quick insight into internal state and operation. The issues appear when you introduce modal workflow, with some features only available in some modes.

Worst offenders in category of hardware equipment are probably guitar multi-effects and synthesizer workstations. They cram so much functionality with so little thought given to flow and usability.