If you see other DJs using more than one MIDI controller, it just means that they want to assign functions that they couldn’t assign to the controller that they already use. It can also make it easier for them to control their software in a shorter period of time (helpful, if you want to make life mashups for example). It has a lot to do with what you personally need and want. It’s not something that you need, if you don’t see a need of it.
And talking about MIDI controllers, I think it’s also a way to make DJing easier and eventually more creative because of that. You have a screen in front of you that helps you to understand what you just did moving a knob or pressing a button. Additionally you have an easy control over your play lists and you can organize it pretty easy.
If you have any question, feel free to ask 🙂 I hope I could help you a little bit.
