How are dark environments a big problem if you can see the buttons? Touch panel based mixing UIs are not unusual in said spaces; I've seen people using touchscreens instead of physical sliders. Given that, this device would be perfectly usable in a dark mixing studio or similarly poorly lit environment; no less usable than a traditional touchscreen (probably more useful, since they can carve little notches into the buttons so you can feel where they are).

It just doesn't make sense to criticize the lack of tactile feedback when a device like this provides more tactile feedback than traditional touchscreens. That criticism only makes sense if you view it as a replacement for a hardware mixing board, which it obviously isn't.