I noticed when I use the Sekonic meter and their expensive test card for determining exposure, the curve generated off the sensor sometimes follows the S curve as in the film era in the better digital cameras, i.e. a nice toe and shoulder curve roll-off on both. The cheaper cameras may show no shoulder at all, but they may have a toe hence things like clouds and white getting blown out with those cameras.
I’m wondering if the need (fuss?) for linearity with step wedges and their linearization might be at odds with the camera’s sensor that is non-linear, perhaps by the sensor or the internal processing in camera? All the step tablets are good for out of camera work, but once the camera enters, the step tablet might work against the camera’s curve and then needs to be altered for that.
If this makes any sense…