Official comment
Yes, that's the whole idea - you prepare your music in rekordbox and it can be used with any Pioneer DJ product, whether it's a controller or a CDJ, no matter whether you're exporting to a USB device or using a computer linked to the players.
rekordbox is free for linking and exporting, but if you wanted to use the software in performance mode (using the software as a controller for the computer doing all the mixing), that requires a purchase of the DJ plugin.