Either not enough resolution to tweak some nuance or too many rotations needed for a wide swing. Perhaps rotaries with 256+ increments per rotation exist, but I

Either not enough resolution to tweak some nuance or too many rotations needed for a wide swing. Perhaps rotaries with 256+ increments per rotation exist, but I think most are much lower. A sample I just checked seems to have 64 per turn, pleasantly surprised but still not really there yet. The 128 values of a legacy MIDI CC are typically over 270 degrees I think.