To make the SQ work well in a radio broadcast environment, I’ve implemented various featured which work by sending midi to the SQ, for things like loudspeaker monitor control. In order to implement polarity reverse on one monitor speaker, I have to waste an input channel – sending the same signal to two input channels, one of which has the polarity reverse switch engaged, and then use midi to flip between the channels.
It we had an effect which was simply a polarity reverse (which I bet will be easy to write!), that could be inserted somewhere and polarity reverse implemented in midi by, for example, changing a mix asignment. The key thing is that I wouldn’t then waste a valuable preamp.