DDJ Controller Question (probably quite stupid)

I'm really new to DJ controller's, but i'm interested in learning more.  Until this time, I've only played on Pioneer decks with my USB-SSD drives plugged into them.  I'd love to know if there is such a controller that I can do that with?  I've been looking at the Pioneer DDJ-1000, which I see has two USB ports on the back, which I guess goes to a computer. However why would there be two?  I would love to just plug my solid state drive in and play from them instead if I could, but those USB ports are not the same as the ones on a CDJ.

Please accept my apologies ahead of time if this all seems to be a rather stupid question.  I've just never been a fan of DJ'ing with my laptop, as I have felt more comfortable with my USB drives.  Any insight on my question would be much appreciated.  Thank you.