Maybe I shouldn't take care of that, but I have just idea to reduce of "flying" midi commands to output devices. Some of gears use only one, or two input channels. As there is input/output filtering for CC/Note/Clock etc comments, it could be useful (for "cleaning" / optimize reason) to select active midi channel(s) and all different that defined will be ignored.
Now if i allow routing from my sequencer (for example 4 channels CH1-CH4) to all synths, this will send every midi commands to each of them, for all channels. If I define that my synth on OUT1 use only CH1 then all commands sent to CH2, CH3, CH4 will be ignored on OUT1.
Now if i allow routing from my sequencer (for example 4 channels CH1-CH4) to all synths, this will send every midi commands to each of them, for all channels. If I define that my synth on OUT1 use only CH1 then all commands sent to CH2, CH3, CH4 will be ignored on OUT1.