Ummm....actually I use it quite a bit (channel-based plugins), mostly for instruments that use multiple samples that I dont want using the same effects.
For example, I make one Instrument that has an array of single-use samples. But one sample I want on a delay and another a reverb and another on a heavier reverb and a flanger. Channel-based plugins allow me to assign a plugin (or the first of a plugin chain) to different channels for use with one sample in a given Instrument.
So why dont I just make all the samples their own Instruments? Because it's extra steps and there is no point-and-click Instrument list for editing individual samples at the Instrument level. (This workaround disappears when the Instrument tab allows me to choose the desired Instrument with one mouseclick.)
Until the Instrument tab is made more efficient, please dont take away channel-based plugin assignment...