As someone who uses a USB equivalent to this piece of hardware (in my case, a Behringer UMC1820): having MIDI and audio inputs on the same interface is a nice convenience feature. Avoids needing to use up multiple ports on the host machine, and avoids a lot of the time synchronization issues that arise with trying to use multiple interfaces at once.

Thank you! You’re right, I didn’t discuss the MIDI implementation in the blog post. Right now it’s a little primitive but functional. Each MIDI message (e.g 3 byte note-on message) maps to 1 UDP packet. I have a simple script on the host side that interfaces these UDP packets with an ALSA loopback MIDI interface.

Probably for the same reason MADI also has MIDI, for sending control messages.