This is more of a request for the developers. It's a feature I've used in previous versions of Cubase. It's been useful to me automating the on/off switch of send, and for what I've been reading, it can't be done on Cakewalk.
I can give you an example on how I use it. When sending a signal to a delay bus, in this way I can send it only in parts I want, for example, on certain parts of vocals. What's the difference between automating the send and muting the delay bus for example? The thing is I need trails. If I mute the track or the delay's output, I lose the delay's trail. That delay in particular, which I like very much, doesn't have an input switch or knob, so I can't automate that.
I know I could automate the send knob by taking it down and up to the levels I need in those particular parts. But I feel it's annoying to do that, when I need to write automation for the delay parts in real time, it just can´t be done with precision. I can write the automation with snapshots, but again, it's slow and time consuming, compared to doing it in real time and then fixing the parts that didn't come out well by hand.
I feel it's a feature that should be added long time ago. I hope they do it soon.