If you're considering adding MIDI capability to your home recording studio then this is a great place to address it.
Unless you have several MIDI devices that need multiple inputs, you can include MIDI in your setup here without having to get a specialized piece of gear.
Some of you may have several MIDI instruments that you want to hook up simultaneously (Synth-aholics Anonymous may be in your near future).
If this sounds like you, you'll want to explore a dedicated MIDI Interface with multiple inputs / outputs.
In other words, the included MIDI inputs on nearly every audio interface will likely be inadequate if you need more than 1 MIDI input and 1 MIDI output for your studio.
The good news is that it's often included so even if you're undecided on the whole MIDI thing it won't cost you any extra to have the option to play around with it.
Most newer MIDI controllers can also be connected to your setup via USB as well, so this can be another option for adding MIDI capability without the standard MIDI I/O.
That brings us to the final piece of the puzzle, mixing capability.