It may sound cool but it's not made to do that.
I would be surprised if anyone thinks that sounds good, or "cool".
No, I mean it sounded better when it was green. I thought it sounded terrible on the red.
Exactly. It's digital clipping and digital clipping sounds dreadful.
The Scarlett 2i2 apparently does not have a MIDI input. Without that, what will I not be able to do?
You won't be able to connect MIDI devices, such as keyboard controllers, sequencers, etc. If you don't know what it's for, the chances are you won't need it.
I also saw something about how you can plug in an mp3 player to some interfaces. Can you do that without a MIDI input? And why would you need an mp3 hookup?
That's unlikely, and I think you are getting confused with amps or multi-fx pedals where they can act as a USB recording device, but can also be used for standalone performance use.
For example, I have a Digitech RP-355 which can be used as an audio interface, but it's main use is as a standalone guitar pedal for practice or performance use. In that case, you can plug an MP3 player into it so you can play along to songs, backing tracks, etc and the unit will mix the MP3 with your guitar. Many modern amps, modelling pedals, etc. do this these days.
But if you are connecting to a PC, you don't need that, because you can play the MP3 on the PC. So units that are designed primarily as PC audio interface don't have that capability.
Bear in mind, some audio interfaces do have multiple cinput channels, so you
could (if you wanted to) connect an MPs player to it and record/playback at the same time, but It's a really tortured way of doing anything; there better ways of doing it (like playing the MP3 directly on the PC).
If it's a backing track, for instance, and you are using a DAW, you can load the backing track into the DAW to play along to.
Cheers,
Keith