Wise people have different opinion, so may be they or you mean something else. Sorry then.
In the MIDI Track Inspector, where there are "C","B","P", "MIDI Channel = None" means no conversion. Each event is sent to the output (VST) as it is defined (each Note has its only MIDI channel information and that information is respected), good for multitimbral track.
When some specific channel is set there, MIDI channel information is not respected and all events are sent on specified channel.