Questions about midi

I’m wondering about the general workflow in recording midi. The odd time that I’ve used synths I’ve patched my keyboard into the synth and recorded the outs of the synth into an audio track in ardour. From what I understand, if I recorded midi tracks, I would have to route the output of the midi track (or external synth)into an audio track and record it before the stereo mix could be exported. Would there really be much of a benefit for me in recording midi other than being able to edit the midi data and switching instruments?
Another question is, how do I get a track to play on a particular midi channel?

For one: You don’t have to route into a separate audio track, if you don’t require the sole audio data for other purposes you could either use a midi track with a plugin that produces audio or you route the output of your synth into a bus.

For two: There are midi lv2 plugins that allow you to force any midi data of any channel in a track into any other channel.

e.g. Robin Gareus’ midifilter

Thank you. I’m guessing that normally you would choose what channel you’re sending midi on from your keyboard. I have a very basic keyboard so that plugin is very useful. I also see now that when you right click on the output of the track, you can insert audio port and then the audio from your plugin instrument can be exported with the rest of the audio tracks.Thanks for your help.