The USB port is indeed a digital audio interface - when you use the unit as a controller for DJ software.
In standalone mode there’s no need, as the unit is designed for use without a computer.
Personally, for streaming I use my Prime 4 as a controller with VDJ, because it doesn’t require any other software. VDJ streams directly to a selection of platforms.
Thanks for your response. It’s highly appreciated. Here’s a little backstory on my question.
I just acquired the Prime 2 as my first piece of DJ equipment after several years of playing my gigs on different CDJs and using the Rekordbox ecosystem.
One of my requirements before purchasing the Prime 2 was the compatibility with Rekordbox. As i want to keep using Rekordbox to organize my music and stay in the ecosystem. I am somehow a bit reluctant to fully switch to Engine, since I am not planning to travel with my Prime 2 to club gigs. I was happily surprised to see how well the Prime 2 works with the Rekordbox data after inserting my main USB. So now I can practice my mixes at home, produce mixtapes and still be able to just travel with a couple of Rekordbox USBs to play gigs on CDJs.
Anyway, my cousin who owns an RX2 showed me how his laptop recognizes his RX2 as an audio output when he starts his Facebook Live or OBS. He only needed to install the RX2 drivers on his laptop.
I presumed this was going to be the case with the Prime 2 and therefore I was slightly surprised to find out my Prime 2 didn’t work like that after installing the drivers for Prime 2 on my laptop.
So now, I have (kind of) concluded that I would still need an external soundcard to connect via USB to my laptop to stream.
I heard that its a bargain for this amount of money. You can also consider Behringer UMC22. It cost a little bit more but It has balance input and good pre amp