Fader Quality
The high quality automated Penny & Giles faders used in large format consoles cost about $1000 each. They have very smooth and silent audio qualities and are touch sensitive. I mean "really" touch sensitive. The conductive fader knobs are electrically connected to a circuit that detects the change in capacity caused by the touch of a finger. Without moving the fader, an LED will light when the fader is touched.
Part of the cost of the fader is the accuracy of the resistive element that passes audio in an analog console. Digital consoles do not pass audio through the fader, so this element can be removed. No signal actually passes through the fader in a digital console. There is only a motor to move the fader and a resistive ladder that sends the current position of the fader to the automation. The level of the audio is changed in the DSP. It doesn’t really matter whether it is a physical fader or a picture of a fader on a screen.
Small format digital consoles use a different method for touch sensitivity, which allows for very inexpensive faders. The automation continuously looks at the position sent by the fader. If the position of the fader is different than where the automation set the fader, then it must have been moved. Notice I said "moved". The fader must be moved. The automation does not actually sense that the fader was touched. The fader movement sensing is usually set to trigger if the fader was moved two fader increments to avoid false movement indications. This means that if you are going to make a small ride in a vocal track, you must move the fader by two steps (0.4 dB in the sweet spot) before the automation knows about the move. This means that the initial movement will be late (it won’t be detected until you have already been moving the fader for awhile) and the change in level may be larger than you want it to be. I always try to move the fader in a hole between lines of the vocal to get the automations attention so that automation data is being written before the spot that I actually want to ride.